Japanese bugle beads are narrower, more consistent in size, and have much smoother holes, relative to Czech bugle beads. 

The "numbering system" to label "sizes" is different for the Japanese than for the Czech.    For example, a size #1 Japanese bugle is noticebly longer and thinner than a size #1 Czech bugle.

The 2.7mm width works well with 11/0 seed beads and larger sizes. [The Czech bugles that we have are 2.7mm wide.]

The 2.0mm width works well with delicas and 15/0 seed beads.