Jump to rules:

• Cantus Firmus
• First Species
• Second Species
• Third Species
• Fourth Species
• Fifth Species

5.1 Overview

The rules specified in this section correspond to the rules in the Preferences Dialog box, where the user may either enable them or disable them. The rules are organized by species, and the rules for each species are only applied to compositions belonging to that species.

Certain rules are present in more than one species. Users are able to disable an instance of one of these rules in one species, but leave it enabled in another, if they wish. Also, although the titles of certain rules may appear similar in different species, their descriptions should still be read, since there are sometimes subtle differences between species.

Some of the rules listed in the following sections are redundant, in the sense that a single error may be detected by multiple rules. This is to allow users to select between slightly different rules based on differing theoretical perspectives. The default preferences are set up to minimize this double counting.
 

5.2 Rules Imposed by the Interface

The interface does not allow the user to make certain mistakes, in order to prevent him or her from inadvertently violating the integrity of the software. The user is still, however, allowed to make many kinds of errors, in order that he or she may learn from mistakes. Those limitations imposed by the interface are as follows:

• Only pitches between C-2 and B3 are permitted.
• Only whole notes are allowed in cantus firmi, and they must be struck on the first beat only.
• Notes belonging to a cantus firmus may not be tied.
• The only time a note may be struck on the last measure of a bar is on its first beat.
• Notes may only be struck on the first beats of all measures in first species compositions.
• Notes may not be struck between beats in third species compositions.
• Notes may only be struck on the first and third beats of all measures in fourth species compositions.
• Notes may only be struck on beats and directly between beats in second and fifth species compositions.
• The only rhythmic durations allowed in the counterpoint are eighth notes, quarter notes, half notes and whole notes.
• Only one note may be struck at a time in a given voice.
• A composition may only have a length of four to twenty measures.
• Both voices in a composition must have the same key, and it cannot change during the piece.
• The only permitted time signature is 4/4.

5.3 Diagnostic Rules for Cantus Firmi

• Check that notes are in correct key: All notes must belong to the given key, with two exceptions: 1) if the composition is in a minor key, then the second to last measure may contain the raised 7th scale degree and 2) if the composition is in a minor key, then the third to last measure may contain the raised 6th scale degree.
• Check that correct note durations are used: Only whole notes can be used.
• Check that notes are struck at correct places: A note must be struck on the first beat of each measure, and notes may only be struck then.
• Check for tied notes: Notes may not be tied.
• Check if rests are present: Rests are not permitted.
• Check range of line: The range of the line should be between a 5th and a 10th.
• Check for repeated notes: The same note may not be struck twice in a row.
• Check horizontal intervals: The only permitted horizontal intervals are minor seconds, major seconds, minor thirds, major thirds, perfect fourths, perfect fifths, minor sixths, major sixths and octaves.
• Check for leaps from the leading tone: It is not permitted to leap from the leading tone.
• Check total number of leaps: There should be between two to four leaps in the line.
• Check for enough large leaps: There should be at least one leap larger than a third in the line.
• Check for too many large leaps: There should be no more than two leaps larger than a fourth in the line.
• Check for too many consecutive leaps: More than two consecutive leaps are not permitted.
• Check for consecutive leaps in the same direction: Two or more consecutive leaps in the same direction are not permitted.
• Check that leaps are filled in: All leaps larger than a third must be filled in by the next note.
• Check that large leaps change direction: Leaps larger than a forth should move in the direction opposite to the direction of the motion preceding them.
• Check that direction is changed after a leap: All leaps larger than a third must be followed by a change of direction.
• Check that the first note is the tonic: The first note of the line must be the tonic and it must be on the first beat of the piece.
• Check that the last note is the tonic: The last note of the line must be the tonic and it must be on the first beat of the last bar.
• Compare first and last notes: If there are no notes lower than the first note of the line, then the last note of the line must have the same pitch as the first note.
• Check that second to last note is approached properly: The second to last note of the line may not be approached by a leap larger than a third.
• Check that the last note is approached stepwise: The last note of the line must be approached stepwise.
• Check that endings are properly treated in minor keys: If the line is in a minor key, and the second to last note is the seventh scale degree, then this note should be raised a semitone. If the above condition is true and the third to last note is the sixth scale degree, then this note should also be raised a semitone.
• Check for properly treated climax: Every line must contain a climax. It is usually the highest note of the line, but may be the lowest point of the line if the first and last notes of the line are the highest points of the line. The climax note may not be exceeded or repeated anywhere in the line. The climax may not be on the first two or last two notes of the line. The climax may not be on the leading tone in a major key or the raised seventh scale degree in a minor key.
• Check that a note does not reoccur too often: No note should appear more than four times in the same register.
• Check rigorously that a note does not reoccur too often: A note should not appear more than three times in the same register if it is ever used to change direction or is involved in a skip. A note should not appear more than twice in the same register if it is used to change direction or is involved in a skip more than once.
• Check interval outlined by a series of notes: The interval between the first and last notes of a series of notes moving in the same direction should not be dissonant (i.e. tritone, minor 7th or major 7th).
• Check for too many consecutive stepwise notes: There should not be more than five consecutive notes without a leap.
• Check number of consecutive notes moving in the same direction: There should not be more than five consecutive notes without a change of direction.
• Check number of changes of direction: The line should change direction at least twice.
• Check for repetitions of groups of tones: Lines should not contain more than one occurrence of the same three pitches occurring consecutively in the same order.
• Check for ornamentation: Lines may not have ornamentation where two pitches are repeated immediately (e.g. ABAB or BABA).
• Check length of piece: The piece should be between eight and sixteen measures long.

5.4 Diagnostic Rules for First Species: Counterpoint Line Only

• Check that notes are in correct key: All notes must belong to the given key, with two exceptions: 1) if the composition is in a minor key, then the second to last measure may contain the raised 7th scale degree and 2) if the composition is in a minor key, then the third to last measure may contain the raised 6th scale degree.
• Check that correct note durations are used: Only whole notes can be used.
• Check that notes are struck at correct places: A note must be struck on the first beat of each measure, and notes may only be struck then.
• Check that tied notes are used correctly: Notes may only be tied if they have the same pitch, the duration of a note that is tied ahead must be such that it ends when the note that it is tied to starts, rests may not be tied and a note that is tied ahead must have a note ahead of it to receive the tie.
• Check for too many consecutive tied notes: Consecutive ties are not permitted.
• Check for too many tied notes in total: A line should not contain more than two ties in total.
• Check if rests are present: Rests are not permitted.
• Check range of line: The range of the line should be between a 5th and a 10th.
• Check for repeated notes: The same note may not be struck twice in a row unless it is tied.
• Check horizontal intervals: The only permitted horizontal intervals are unisons, minor seconds, major seconds, minor thirds, major thirds, perfect fourths, perfect fifths, minor sixths, major sixths and octaves. Tied notes are also permitted.
• Check for leaps from the leading tone: It is not permitted to leap from the leading tone.
• Check total number of leaps: There should be between two to four leaps in the line.
• Check for enough large leaps: There should be at least one leap larger than a third in the line.
• Check for too many large leaps: There should be no more than two leaps larger than a fourth in the line.
• Check for too many consecutive leaps: More than two consecutive leaps are not permitted.
• Check for consecutive leaps in the same direction: Two or more consecutive leaps in the same direction are not permitted.
• Check that leaps are filled in: All leaps larger than a third must be filled in by the next note.
• Check that large leaps change direction: Leaps larger than a forth should move in the direction opposite to the direction of the motion preceding them.
• Check that direction is changed after a leap: All leaps larger than a third must be followed by a change of direction.
• Check that the last note is the tonic: The last note of the line must be the tonic and it must be on the first beat of the last bar.
• Compare first and last notes: If there are no notes lower than the first note of the line, then the last note of the line must have the same pitch as the first note.
• Check that second to last note is approached properly: The second to last note of the line may not be approached by a leap larger than a third.
• Check that the last note is approached stepwise: The last note of the line must be approached stepwise.
• Check that endings are properly treated in minor keys: If the line is in a minor key, and the second to last note is the seventh scale degree, then this note should be raised a semitone. If the above condition is true and the third to last note is the sixth scale degree, then this note should also be raised a semitone.
• Check for properly treated climax: Every line must contain a climax. It is usually the highest note of the line, but may be the lowest point of the line if the first and last notes of the line are the highest points of the line. The climax note may not be exceeded or repeated anywhere in the line. The climax may not be on the first two or last two notes of the line. The climax may not be on the leading tone in a major key or the raised seventh scale degree in a minor key.
• Check that a note does not reoccur too often: No note should appear more than four times in the same register.
• Check rigorously that a note does not reoccur too often: A note should not appear more than three times in the same register if it is ever used to change direction or is involved in a skip. A note should not appear more than twice in the same register if it is used to change direction or is involved in a skip more than once.
• Check interval outlined by a series of notes: The interval between the first and last notes of a series of notes moving in the same direction should not be dissonant (i.e. tritone, minor 7th or major 7th).
• Check for too many consecutive stepwise notes: There should not be more than five consecutive notes without a leap.
• Check number of consecutive notes moving in the same direction: There should not be more than five consecutive notes without a change of direction.
• Check number of changes of direction: The line should change direction at least twice.
• Check for repetitions of groups of tones: Lines should not contain more than one occurrence of the same three pitches occurring consecutively in the same order.
• Check for ornamentation: Lines may not have ornamentation where two pitches are repeated immediately (e.g. ABAB or BABA).

5.5 Diagnostic Rules for First Species: Both Lines

• Check vertical intervals: The only permitted vertical intervals are unisons, minor and major thirds, perfect fifths, minor and major sixths, octaves, minor and major tenths and perfect twelfths.
• Check unisons: Vertical unisons may only be present in the first and last measures of the piece.
• Check that vertical twelfths are treated properly: Vertical perfect twelfths are only permitted in the climax of the counterpoint, and they may not leap to or be leapt from a perfect fifth..
• Check that perfect intervals are approached properly: Perfect intervals must be approached with contrary or oblique motion. This rules out the possibility of parallel fifths or octaves.
• Check successive unisons and octaves: Vertical octaves may not be followed by unisons and vertical unisons may not be followed by octaves.
• Check for too many consecutive identical intervals: More than three consecutive identical vertical intervals (e.g. four thirds in a row) should not be present.
• Check for too much consecutive parallel motion: A piece should not have more than three pairs of notes in a row that move using parallel motion.
• Check leaps from perfect intervals: Notes in the counterpoint that are part of vertical perfect intervals should not be leapt to or from.
• Check lines for improper simultaneous leaps: If there is a horizontal leap in one line, then the other line should move stepwise if the leap is greater than a forth or if the lines move with similar motion.
• Check for simultaneous climaxes: The counterpoint and the cantus firmus should not have their climaxes occur simultaneously.
• Check for voice crossing: A note in the bottom line may never be above the corresponding note in the top line and a note in the top line may never be below the corresponding note in the bottom line.
• Check for voice overlap: A note in the bottom line may not move up past where the last note of the top line was just previously and a note in the top line may not move down below where the last note of the bottom line was just previously.
• Check the beginning interval: The first vertical interval of the piece must be a unison, a perfect fifth or an octave. A perfect fifth is only permitted when the counterpoint is above the cantus.
• Check the last interval: The last vertical interval of the piece must be a unison or an octave.
• Check the approach to the last interval: The last interval of the piece must be approached with contrary motion.

5.6 Diagnostic Rules for Second Species: Counterpoint Line Only

• Check that notes are in correct key: All notes must belong to the given key, with two exceptions: 1) if the composition is in a minor key, then the second to last measure may contain the raised 7th scale degree and 2) if the composition is in a minor key, then the third to last measure may contain the raised 6th scale degree.
• Check that correct note durations are used: Only whole notes and half notes are permitted. Whole notes are only permitted in the last two measures of the line and half notes are not permitted in the last measure of the line.
• Check that notes are struck at correct places: All parts of the line must have a note sounding or be covered by a rest at all times. Multiple notes and/or rests may not overlap in a single line.
• Check for tied notes: Notes may not be tied.
• Check if rests are present: The only rest permitted is a half rest on the first beat of the line.
• Check range of line: The range of the line should be between a 5th and a 10th.
• Check for repeated notes: The same note may not be struck twice in a row.
• Check horizontal intervals: The only permitted horizontal intervals are minor seconds, major seconds, minor thirds, major thirds, perfect fourths, perfect fifths, minor sixths, major sixths and octaves.
• Check for leaps from the leading tone: It is not permitted to leap from the leading tone.
• Check for enough large leaps: There should be at least one leap larger than a third in the line.
• Check for too many large leaps: There should be no more than two leaps larger than a fourth in the line.
• Check for too many consecutive leaps: There should not be more than two consecutive leaps.
• Check for consecutive leaps in the same direction: Two or more consecutive leaps in the same direction are only permitted if the following conditions are met: a) the first leap starts on the first beat of a measure and the second leap ends on the first beat of a measure and b) the combined interval of the two leaps is consonant (i.e. perfect fifth, minor sixth, major  sixth or octave).
• Check for leaps across measure lines: Leaps across measure lines are only permitted if the leap is a fourth or smaller and the direction of motion is changed immediately after the leap.
• Check that leaps are filled in: All leaps larger than a fourth must be filled in by the next note.
• Check that leaps of a fourth are treated properly: Leaps of a fourth must be filled in unless the following conditions are met: 1) the note after the leap is approached stepwise,  2) there is a change of direction following the note following the leap and  3) the leap is in the direction opposite to the direction of motion preceding the leap.
• Check that large leaps change direction: Leaps larger than a fourth should move in the direction opposite to the direction of the motion preceding them.
• Check that the last note is the tonic: The last note of the line must be the tonic and it must be on the first beat of the last bar.
• Compare first and last notes: If there are no notes lower than the first note of the line, then the last note of the line must have the same pitch as the first note.
• Check that second to last note is approached properly: The second to last note of the line may not be approached by a leap larger than a third.
• Check that the last note is approached stepwise: The last note of the line must be approached stepwise.
• Check that endings are properly treated in minor keys: If the line is in a minor key, and the second to last note is the seventh scale degree, then this note should be raised a semitone. If the above condition is true and the third to last note is the sixth scale degree, then this note should also be raised a semitone.
• Check for properly treated climax: Every line must contain a climax. It is usually the highest note of the line, but may be the lowest point of the line if the first and last notes of the line are the highest points of the line. The climax note may not be exceeded or repeated anywhere in the line. The climax may not be on the first two or last two notes of the line. The climax may not be on the leading tone in a major key or the raised seventh scale degree in a minor key.
• Check interval outlined by a series of notes: The interval between the first and last notes of a series of notes moving in the same direction should not be dissonant (i.e. tritone, minor 7th or major 7th).
• Check for too many consecutive stepwise notes: There should not be more than six consecutive notes without a leap.
• Check number of consecutive notes moving in the same direction: There should not be more than six consecutive notes without a change of direction.
• Check number of changes of direction: The line should change direction at least twice.
• Check for repetitions of groups of tones: Lines should not contain more than one occurrence of the same three pitches occurring consecutively in the same order.
• Check for ornamentation: Lines may not have ornamentation where two pitches are repeated immediately (e.g. ABAB or BABA).

5.7 Diagnostic Rules for Second Species: Both Lines

• Check vertical intervals: Vertical intervals other than unisons, minor and major thirds, perfect fifths, minor and major sixths, octaves and the multiples of these intervals are only permitted on weak beats, and must be approached and left with stepwise motion. Intervals greater than perfect twelfths should generally be avoided.
• Check unisons: Vertical unisons are only permitted on weak beaks, except for on the first beats of the first  and last measures, where they may be present. If they occur on weak beats, they must be left by stepwise motion in the opposite direction to that by which they were approached.
• Check that vertical twelfths are treated properly: Vertical perfect twelfths are only permitted in the climax of the counterpoint.
• Check that perfect intervals are approached properly: Perfect intervals must be approached with contrary or oblique motion. This rules out the possibility of parallel fifths or octaves, which are absolutely forbidden.
• Check for parallel perfect intervals on successive strong beats: Parallel fifths or octaves that occur on successive first beats should be avoided, regardless of the half note separating them. Although these are permissible occasionally, they should not be emphasized or used frequently.
• Check for too many consecutive identical intervals: Should not have the same vertical interval occurring on the first beats of more than three consecutive measures.
• Check leaps from perfect intervals: If there is a perfect vertical interval on the first beat of a measure, then the counterpoint note should not be leaped to or from. This is sometimes permissible if the leap is small and the direction of motion is changed, but it should generally be avoided.
• Check for simultaneous climaxes: The counterpoint and the cantus firmus should not have their climaxes occur simultaneously.
• Check for voice crossing: A note in the bottom line may never be above the corresponding note in the top line and a note in the top line may never be below the corresponding note in the bottom line.
• Check for voice overlap: A note in the bottom line may not move up past where the last note of the top line was just previously and a note in the top line may not move down below where the last note of the bottom line was just previously.
• Check the beginning interval: The first vertical interval of the piece must be a unison, a perfect fifth or an octave. A perfect fifth is only permitted when the counterpoint is above the cantus.
• Check the last interval: The interval of the notes struck on the first beat of the last measure of the piece must be a unison or an octave.
• Check the approach to the last interval: The notes on the first beat of the last measure must be approached with contrary motion.

5.8 Diagnostic Rules for Third Species: Counterpoint Line Only

• Check that notes are in correct key: All notes must belong to the given key, with two exceptions: 1) if the composition is in a minor key, then the second to last measure may contain the raised 7th scale degree and 2) if the composition is in a minor key, then the third to last measure may contain the raised 6th scale degree.
• Check that correct note durations are used: Only whole notes and quarter notes are permitted. A whole note may only be used in the last measure of the line and quarter notes are not permitted in the last measure of the line.
• Check that notes are struck at correct places: All parts of the line must have a note sounding or be covered by a rest at all times. Multiple notes and/or rests may not overlap in a single line.
• Check for tied notes: Notes may not be tied.
• Check if rests are present: The only rest permitted is a quarter rest on the first beat of the line.
• Check range of line: The range of the line should be between a 5th and a 10th.
• Check for repeated notes: The same note may not be struck twice in a row.
• Check horizontal intervals: The only permitted horizontal intervals are minor seconds, major seconds, minor thirds, major thirds, perfect fourths, perfect fifths, minor sixths, major sixths and octaves.
• Check for leaps from the leading tone: It is not permitted to leap from the leading tone.
• Check for enough large leaps: There should be at least one leap larger than a third in the line.
• Check for too many large leaps: There should be no more than two leaps larger than a fourth in the line.
• Check for too many consecutive leaps: There should not be more than two consecutive leaps.
• Check for consecutive leaps in the same direction: Two consecutive leaps in the same direction are not permitted.
• Check for leaps across bar lines: Leaps across bar lines are only permitted if the leap is a fourth or smaller and  is in the direction of motion opposite to the direction of motion preceding it..
• Check that leaps are filled in: Leaps larger than a third should be filled in by the next note.
• Check that leaps change direction: Leaps should generally move in the direction opposite to the direction of motion preceding them. This is occasionally acceptable, however, if it is not preceded by more than two or three notes moving stepwise in the same direction.
• Check that the last note is the tonic: The last note of the line must be the tonic and it must be on the first beat of the last bar.
• Compare first and last notes: If there are no notes lower than the first note of the line, then the last note of the line must have the same pitch as the first note.
• Check that second to last note is approached properly: The second to last note of the line may not be approached by a leap larger than a third.
• Check that the last note is approached stepwise: The last note of the line must be approached stepwise.
• Check that endings are properly treated in minor keys: If the line is in a minor key, and the second to last note is the seventh scale degree, then this note should be raised a semitone. If the above condition is true and the third to last note is the sixth scale degree, then this note should also be raised a semitone.
• Check for properly treated climax: Every line must contain a climax. It is usually the highest note of the line, but may be the lowest point of the line if the first and last notes of the line are the highest points of the line. The climax note may not be exceeded or repeated anywhere in the line (decoration with a neighbour note is not considered repetition). The climax must be on a metrically strong beat (the first or third beat). The climax may not be on the first two or last two notes of the line. The climax may not be on the leading tone in a major key or the raised seventh scale degree in a minor key.
• Check interval outlined by a series of notes: The interval between the first and last notes of a series of notes moving in the same direction should not be dissonant (i.e. tritone, minor 7th or major 7th).
• Check number of consecutive notes moving in the same direction: There should not be more than six consecutive notes without a change of direction.
• Check number of changes of direction: The line should change direction at least twice.
• Check for ornamentation: Lines may not have ornamentation where two pitches are repeated immediately (e.g. ABAB or BABA).

5.9 Diagnostic Rules for Third Species: Both Lines

• Check vertical intervals: Vertical intervals other than unisons, minor and major thirds, perfect fifths, minor and major sixths, octaves and the multiples of these intervals are only permitted on weak beats and must be approached and left with stepwise motion, unless they are part of a double neighbour or a nota camiata.
• Check unisons: Vertical unisons are not permitted on the first beat of measures, except in the case of the first and last measures, where they may be used on the first beats.
• Check nota cambiata: The first and third tones of a nota cambiata must always be consonant. The first tone of a nota cambiata must fall on the first beat of a measure.
• Check double neighbour: The first tone of a double neighbour must fall on the first beat of a measure, the tone being decorated must be consonant and the motion immediately after a double neighbour must be stepwise and must continue the direction of motion. It is also preferable for the upper neighbour to precede the lower neighbour and for one of the neighbours to be a semitone from the note being decorated.
• Check dissonant neighbour notes: Dissonant neighbour notes on the third beat of  measures should generally be avoided.
• Check distance between lines: Vertical intervals greater than perfect twelfths should generally be avoided
• Check that perfect intervals are approached properly: Perfect intervals should be approached with contrary or oblique motion.
• Check for parallel perfect intervals: Consecutive unisons, fifths and octaves are forbidden.
• Check separation between perfect intervals: Two vertical unisons, fifths or octaves separated by only one tone should be avoided.
• Check for parallel perfect intervals on successive strong beats: Parallel fifths or octaves that occur on successive first beats should be avoided, regardless of the notes separating them. Although these are permissible occasionally, they should not be emphasized nor used frequently.
• Check for too many consecutive perfect intervals: The same vertical perfect interval should not occur on the first beats of more than two consecutive measures.
• Check leaps from perfect intervals: If there is a perfect vertical interval on the first beat of a measure, then the counterpoint note should not be leaped to or from. This is sometimes permissible if the leap is small and the direction of motion is changed, but it should generally be avoided.
• Check for simultaneous climaxes: The counterpoint and the cantus firmus should not have their climaxes occur simultaneously.
• Check for voice crossing: A note in the bottom line may never be above the corresponding note in the top line and a note in the top line may never be below the corresponding note in the bottom line.
• Check for voice overlap: A note in the bottom line may not move up past where the last note of the top line was just previously and a note in the top line may not move down below where the last note of the bottom line was just previously.
• Check the beginning interval: The first vertical interval of the piece must be a unison, a perfect fifth, an octave or a perfect twelfth. A perfect fifth or twelfth is only permitted when the counterpoint is above the cantus.
• Check the last interval: The interval of the notes struck on the first beat of the last measure of the piece must be a unison or an octave.
• Check the approach to the last interval: The notes on the first beat of the last measure must be approached with contrary motion.

5.10 Diagnostic Rules for Fourth Species: Counterpoint Line Only

• Check that notes are in correct key: All notes must belong to the given key, with two exceptions: 1) if the composition is in a minor key, then the second to last measure may contain the raised 7th scale degree and 2) if the composition is in a minor key, then the third to last measure may contain the raised 6th scale degree.
• Check that correct note durations are used: All notes must be half notes, except for the last note, which must be a whole note and must be struck on the first beat of the last measure.
• Check that notes are struck at correct places: All parts of the line must have a note sounding or be covered by a rest at all times. Multiple notes and/or rests may not overlap in a single line.
• Check that tied notes are used correctly: Notes may only be tied if they have the same pitch, the duration of a note that is tied ahead must be such that it ends when the note that it is tied to starts, rests may not be tied and a note that is tied ahead must have a note ahead of it to receive the tie.
• Check for consecutive tied notes: A note may not be tied twice consecutively.
• Check that ties are properly placed: Notes on strong beats may not be tied ahead to notes on weak beats.
• Check that species is not broken too frequently: A line should not contain more than eight notes that are not involved in a suspension.
• Check consecutive notes involved in broken species: There may not be more than two consecutive notes that are not involved in a suspension.
• Check if rests are present: There must be a half rest on the first beat of the line and this is the only place where a rest may be present.
• Check range of line: The range of the line should be between a 5th and a 10th.
• Check for repeated notes: The same note may not be struck twice in a row unless it is tied.
• Check horizontal intervals: The only permitted horizontal intervals are minor seconds, major seconds, minor thirds, major thirds, perfect fourths, perfect fifths, minor sixths, major sixths and octaves. Tied notes are also permitted.
• Check for leaps from the leading tone: It is not permitted to leap from the leading tone.
• Check for enough large leaps: There should be at least one leap larger than a third in the line.
• Check for too many large leaps: There should be no more than two leaps larger than a fourth in the line.
• Check for too many consecutive leaps: There should not be more than two consecutive leaps.
• Check for consecutive leaps in the same direction: More than two consecutive leaps in the same direction should be avoided.
• Check for leaps across measure lines: Leaps across measure lines are only permitted if the leap is a fourth or smaller and the direction of motion is changed immediately after the leap.
• Check that the last note is the tonic: The last note of the line must be the tonic and it must be on the first beat of the last bar.
• Compare first and last notes: If there are no notes lower than the first note of the line, then the last note of the line must have the same pitch as the first note.
• Check that the last note is approached properly: The last note of the line may not be approached by leap and may not be involved in a suspension.
• Check that endings are properly treated in minor keys: If the line is in a minor key, and the second to last note is the seventh scale degree, then this note should be raised a semitone. If the above condition is true and the third to last note is the sixth scale degree, then this note should also be raised a semitone.
• Check for properly treated climax: Every line must contain a climax. It is usually the highest note of the line, but may be the lowest point of the line if the first and last notes of the line are the highest points of the line. The climax note may not be exceeded or repeated anywhere in the line. The climax may not be on the first two or last two notes of the line. The climax may not be on the leading tone in a major key or the raised seventh scale degree in a minor key.
• Check for too many consecutive stepwise notes: There should not be more than six consecutive notes without a leap.
• Check number of consecutive notes moving in the same direction: There should not be more than six consecutive notes without a change of direction.
• Check number of changes of direction: The line should change direction at least twice.
• Check for ornamentation: Lines may not have ornamentation where two pitches are repeated immediately (e.g. ABAB or BABA).

5.11 Diagnostic Rules for Fourth Species: Both Lines

• Check vertical intervals: Vertical intervals other than unisons, minor and major thirds, perfect fifths, minor and major sixths, octaves and the multiples of these intervals are only permitted on strong beats when they are involved in a dissonant suspension, and they are only permitted on weak beats when they are not part of a suspension (i.e. species has been broken) and are approached and left with stepwise motion.
• Check distance between lines: Vertical intervals greater than perfect twelfths should generally be avoided
• Check that perfect intervals are approached properly: If species is broken, perfect intervals must be approached with contrary or oblique motion. This rules out the possibility of parallel fifths or octaves, which are absolutely forbidden.
• Check for voice crossing: A note in the bottom line may never be above the corresponding note in the top line and a note in the top line may never be below the corresponding note in the bottom line.
• Check for voice overlap: A note in the bottom line may not move up past where the last note of the top line was just previously and a note in the top line may not move down below where the last note of the bottom line was just previously.
• Check the beginning interval: The first vertical interval of the piece must be a unison, a perfect fifth or an octave. A perfect fifth is only permitted when the counterpoint is above the cantus.
• Check the last interval: The interval of the notes struck on the first beat of the last measure of the piece must be a unison or an octave.
• Check the approach to the last interval: The notes on the first beat of the last measure must be approached with contrary motion.
• Check that dissonant suspensions resolve properly: Dissonant suspensions must resolve downwards by step.
• Check series of suspensions: More than three suspensions of the same type occurring consecutively should generally be avoided.
• Check consecutive 9-8 suspensions: Consecutive 9-8 suspensions are not permitted.
• Check consecutive 2-1 suspensions: Consecutive 2-1 suspensions are not permitted.
• Check consecutive 4-5 suspensions: Consecutive 4-5 suspensions are not permitted.
• Check for 7-8 suspensions: 7-8 suspensions are forbidden.
• Check for 2-1 suspensions: 2-1 suspensions should be avoided if possible.
• Check for enough consonant suspensions: There should be at least one consonant suspension in the piece.
• Check for enough dissonant suspensions: There should be more dissonant suspensions than consonant suspensions in the piece.

5.12 Diagnostic Rules for Fifth Species: Counterpoint Line Only

• Check that notes are in correct key: All notes must belong to the given key, with two exceptions: 1) if the composition is in a minor key, then the second to last measure may contain the raised 7th scale degree and 2) if the composition is in a minor key, then the third to last measure may contain the raised 6th scale degree.
• Check for whole notes: A whole note is the only duration permitted in the last measure of a line and this is the only place where a whole note may be used.
• Check that notes are struck at correct places: All parts of the line must have a note sounding or be covered by a rest at all times. Multiple notes and/or rests may not overlap in a single line.
• Check rhythmic configuration of first measure: The first measure of the line must contain one of the following rhythmic configurations: two half notes, a half rest followed by a half note, a quarter rest followed by three quarter notes or four quarter notes. If the measure is ended with a half note, it may be tied ahead or not tied ahead.
• Check rhythmic configuration of other measures: Only the following rhythmic configurations are permitted in measures other than the first: Measures with four quarter notes, measures with two half notes with the second not tied, measures with a half note followed by two quarter notes, measures with a half note followed by a quarter note a followed by two eighth notes, measures with a quarter note followed by two eighth notes followed by two quarter notes, measures with three quarter notes followed by two eighth notes, measures with two quarter notes followed by a tied half note, measures with a half note followed by a tied half note, measures with a quarter note followed by two eighth notes followed by a tied half note, measures with a quarter note followed by two eighth notes followed by an untied half note and measures with just a half note.
• Check for prolonged use of a single rhythmic value: A single rhythmic note value (i.e. all quarter notes or all half notes) should not continue without variation for more than two measures.
• Check rhythmic variation: Not more than roughly a third of a line should consist of measures with only a single type of rhythmic note value (i.e. all quarter notes or all half notes).
• Check for changes of rhythmic configuration: Two consecutive measures with the same rhythmic configuration are not permitted unless they are made up entirely of notes with only a single rhythmic value (i.e. all quarter notes or all half notes).
• Check eighth notes: Eighth notes must occur two at a time and they must move by step. A leap to the first eighth note is sometimes permitted, but a leap between the eighth notes or from the second eighth note is forbidden.
• Check that tied notes are used correctly: Notes may only be tied if they have the same pitch, the duration of a note that is tied ahead must be such that it ends when the note that it is tied to starts, rests may not be tied and a note that is tied ahead must have a note ahead of it to receive the tie.
• Check for consecutive tied notes: A note may not be tied twice consecutively.
• Check that ties are rhythmically correct: Only half notes struck on the third beat of a measure may be tied ahead.
• Check if rests are present: The only rest permitted is either a quarter rest or a half rest on the first beat of the line.
• Check range of line: The range of the line should be between a 5th and a 10th.
• Check for repeated notes: The same note may not be struck twice in a row unless it is tied.
• Check horizontal intervals: The only permitted horizontal intervals are minor seconds, major seconds, minor thirds, major thirds, perfect fourths, perfect fifths, minor sixths, major sixths and octaves.
• Check for leaps from the leading tone: It is not permitted to leap from the leading tone.
• Check for enough large leaps: There should be at least one leap larger than a third in the line.
• Check for too many large leaps: There should be no more than two leaps larger than a fourth in the line.
• Check for too many consecutive leaps: There should not be more than two consecutive leaps.
• Check for consecutive leaps in the same direction: Two consecutive leaps in the same direction are not permitted.
• Check for leaps across bar lines: Leaps across bar lines are only permitted if the leap is a fourth or smaller and  is in the direction of motion opposite to the direction of motion preceding it.
• Check that leaps are filled in: Leaps larger than a third should be filled in by the next note.
• Check that large leaps change direction: Leaps larger than a fourth should move in the direction opposite to the direction of the motion preceding them.
• Check that the last note is the tonic: The last note of the line must be the tonic and it must be on the first beat of the last bar.
• Compare first and last notes: If there are no notes lower than the first note of the line, then the last note of the line must have the same pitch as the first note.
• Check that second to last note is approached properly: The second to last note of the line may not be approached by a leap larger than a third.
• Check that the last note is approached stepwise: The last note of the line must be approached stepwise.
• Check that endings are properly treated in minor keys: If the line is in a minor key, and the second to last note is the seventh scale degree, then this note should be raised a semitone. If the above condition is true and the third to last note is the sixth scale degree, then this note should also be raised a semitone.
• Check for properly treated climax: Every line must contain a climax. It is usually the highest note of the line, but may be the lowest point of the line if the first and last notes of the line are the highest points of the line. The climax note may not be exceeded or repeated anywhere in the line (decoration with a neighbour note is not considered repetition). The climax must be on a metrically strong beat (the first or third beat). The climax may not be on the first two or last two notes of the line. The climax may not be on the leading tone in a major key or the raised seventh scale degree in a minor key.
• Check interval outlined by a series of notes: The interval between the first and last notes of a series of notes moving in the same direction should not be dissonant (i.e. tritone, minor 7th or major 7th).
• Check number of consecutive notes moving in the same direction: There should not be more than six consecutive notes without a change of direction.
• Check number of changes of direction: The line should change direction at least twice.
• Check for ornamentation: Lines may not have ornamentation where two pitches are repeated immediately (e.g. ABAB or BABA).

5.13 Diagnostic Rules for Fifth Species: Both Lines

• Check vertical intervals: Vertical intervals other than unisons, minor and major thirds, perfect fifths, minor and major sixths, octaves and the multiples of these intervals are only permitted on the first beat of a measure when they are tied back. Dissonant intervals are only permitted on other beats when they are not tied forward and are approached and left with stepwise motion (unless they are part of a double neighbour or a nota camiata, in which case there may be a leap between dissonances).
• Check unisons: Vertical unisons are not permitted on the first beat of measures unless they are part of suspensions or are in the first or last measures. Unisons are only permitted on other beats if they are tied over or are followed by stepwise motion.
• Check nota cambiata: The first and third tones of a nota cambiata must always be consonant. The first tone of a nota cambiata must fall on the first beat of a measure.
• Check double neighbour: The first tone of a double neighbour must fall on the first beat of a measure, the tone being decorated must be consonant and the motion immediately after a double neighbour must be stepwise and must continue the direction of motion. It is also preferable for the upper neighbour to precede the lower neighbour and for one of the neighbours to be a semitone from the note being decorated.
• Check dissonant neighbour notes: Dissonant neighbour notes on the third beat of  measures should generally be avoided.
• Check distance between lines: Vertical intervals greater than perfect twelfths should generally be avoided
• Check that perfect intervals are approached properly: Perfect intervals not involved in suspensions should be approached with contrary or oblique motion.
• Check for parallel perfect intervals: Consecutive unisons, fifths and octaves are forbidden.
• Check separation between perfect intervals: Two vertical unisons, fifths or octaves separated by only one tone should be avoided.
• Check for too many consecutive perfect intervals: The same vertical perfect interval should not occur on the first beats of more than two consecutive measures.
• Check leaps from perfect intervals: If there is a perfect vertical interval on the first beat of a measure, then the counterpoint note should not be leaped to or from. This is sometimes permissible if the leap is small and the direction of motion is changed, but it should generally be avoided.
• Check for simultaneous climaxes: The counterpoint and the cantus firmus should not have their climaxes occur simultaneously.
• Check for voice crossing: A note in the bottom line may never be above the corresponding note in the top line and a note in the top line may never be below the corresponding note in the bottom line.
• Check for voice overlap: A note in the bottom line may not move up past where the last note of the top line was just previously and a note in the top line may not move down below where the last note of the bottom line was just previously.
• Check the beginning interval: The first vertical interval of the piece must be a unison, a perfect fifth, an octave or a perfect twelfth. A perfect fifth or twelfth is only permitted when the counterpoint is above the cantus.
• Check the last interval: The interval of the notes struck on the first beat of the last measure of the piece must be a unison or an octave.
• Check the approach to the last interval: The notes on the first beat of the last measure must be approached with contrary motion.
• Check that dissonant suspensions resolve properly: Dissonant suspensions must resolve downwards by step to the third beat of the measure, even if the suspension is decorated on the second beat.
• Check series of suspensions: More than three suspensions of the same type occurring consecutively should generally be avoided.
• Check consecutive 9-8 suspensions: Consecutive 9-8 suspensions are not permitted.
• Check consecutive 2-1 suspensions: Consecutive 2-1 suspensions are not permitted.
• Check consecutive 4-5 suspensions: Consecutive 4-5 suspensions are not permitted.
• Check for 7-8 suspensions: 7-8 suspensions are forbidden.
• Check for 2-1 suspensions: 2-1 suspensions should be avoided if possible.