“If you have but 5 minutes in your day to meditate, play Choshi.”
This advice was given by Shimura Zempo during a shakuhachi class in Prague in 2010. That’s when I started playing the Choshi pieces (or other short preludes) for meditation. I play one of them every day (every day I can practice), and I always begin a solo concert with one of them.
They are played to warm-up the flute, as a prelude to longer pieces. They are easy to remember because of their simple structure. I recommend to play them by heart, in order to fully focus on the breathing.
Make a ritual of it (zen rule # 6): play everyday the same meditation prelude for a week or more, before starting the studying part of your practice.
Here you can find information and recordings of Kyorei, Honte Choshi, Yamato Choshi, HiFuMi Cho.