A Japanese endblown flute based on Chinese models. "Shaku" means basically "one" foot (or thereabouts) and "eight" inches (or thereabouts), which describes the length of the bamboo, which is keyed to C but in the pentatonic scale.
Yes, RalfM, you are right. I had been just playing my ni-shaku which is tuned to D.

Here is a list of lengths and tunings:

  • Key G; i-shaku-san-sun; 1.3', 40 cm
  • Key F#; i-shaku-yon-sun; 1.4', 43 cm
  • Key F; i-shaku-go-sun; 1.5', 46 cm.
  • Key E; i-shaku-roku-sun; 1.6', 48.5 cm
  • Key Eb; i-shaku-nana-sun; 1.7', 52 cm
  • Key D; i-shaku-ha-sun; 1.8', 54.5 cm
  • Key C#; i-shaku-kyu-sun; 1.9', 59 cm
  • Key C; ni-shaku; 2', 62.5 cm
  • Key B; ni-shaku-i-sun; 2.1', 66 cm
  • Key Bb; ni-shaku-san-sun; 2.2-2.3', 70 cm
  • Key A; ni-shaku-yon-sun; 2.4', 75 cm