Genkei shisu (original shape index)

The original shape index (genkei shisu) is an indicator of how much of the shape of brown rice is retained by polished (milled) white rice. It is calculated by comparing the length, width, and thickness of the white rice with the corresponding dimensions of the brown rice. Specifically, the original shape index LW is the ratio of length to width of the white rice divided by the ratio of length to width of the brown rice, and the original shape index WT is the ratio of width to thickness of the white rice divided by the ratio of width to thickness of the brown rice. The closer the index value is to 1, the better the white rice retains the shape of the brown rice, and this is considered a factor that affects the quality and texture of the rice. Rice with a high original shape index is said to cook well and have a satisfying bite, so it is also an important indicator for rice used as a raw material for sake.