It's a traditional Japanese handle that's rounded on one side and flat on the other (a "D" shape ), primarily designed for right-handed users. It offers excellent ergonomics and control while cutting.
How it affects use
The handle changes balance, grip and control. On a Japanese knife it is not just decorative; it helps determine whether the piece feels comfortable for long, precise or repeated cuts.
What to read in the product details
Check material, shape, transition into the blade and care notes. Woods and natural materials benefit from careful drying and avoiding prolonged humidity.