I recently purchased a few Japanese chisels of supposed high quality, but their cutting edges don't hold up to hardwoods as well as I'd like.
Some Japanese chisels require steeper bevel angles than others.
Start with an angle of 28 and gradually increase the bevel angle until the chisel holds an edge well when you cut hardwoods. Don't make the angle any steeper than necessary. The laminated blade's hard steel layer should be backed by the full mass of the mild steel layer to give the edge maximum durability. A flat bevel also allows you to use the tool with its bevel down to pare accurately into tight spaces. Grind with a light touch to avoid burning the steel and to avoid removing any more steel than necessary.