The upper mordent (German, Pralltriller) consists of the principal note, the note of the scale above, and the principal note again, played as quickly as possible in the time of the principal note. The third note should be of longer duration than the preceding ones, and should bear the accent.
When the note, upon which the upper mordent is placed is preceded by an appoggiatura, the mordent is delayed.
When the upper mordent is placed before a chord, it only affects the particular note before which it is placed.
The upper mordent is sometimes indicated by the actual notes printed in small type.
When an accidental is placed above the upper mordent sign, it signifies that the upper note is to be raised or lowered a semitone.
A good effect is often produced by beginning the upper mordent with a short appoggiatura when the principal note is preceded by one of the same pitch.
In some cases when it is impossible to execute the three notes of the upper mordent owing to the speed of the movement, an acciaccatura only may be played.