This is just another reference post.
It turns out there are three ways frequently used in Jodo Shu Buddhism:
- Jūnen (十念) – ten recitations of the nembutsu. The first eight go like “na-mu-a-mi-da-bu”, but in the ninth recitation you say “na-mu-a-mi-da-bu-tsu“. The tenth and last recitation drops the “tsu” again, and is said more drawn out, and is followed by a bow. This is the most common form of recitation.
- Nembutsu ichi-e (念仏一会) – this, as far as I can tell, is just a free-form recitation of the nembutsu. Recite “na-mu-a-mi-da-bu” over and over again as much as you like. The last namu amida bu is more drawn out and followed by a bow.
- Sanshōrai (三唱礼) – this is to recite the nembutsu 9 times total, in 3 groups of 3 recitations. These recitations of “na-mu-a-mi-da-bu” are slow and drawn out, and at the end of each third recitation, you bow before an image of Amitabha Buddha. Thus, you would bow three times total. This particular chanting style is supposed to symbolize the 9 states of rebirth in the Pure Land as specified in the Contemplation of Amitabha Sutra.
The home page linked above lists these as well, but I was curious to see how other Japanese-language sites describe these three styles of recitation, and tried my best to explain them here as well. The good news is that the three are pretty consistent across Jodo Shu Buddhism as far as I can tell.
Edit: more details on three kinds of nembutsu recitation.