I think it is built into the Japanese character to fuss over stuff like this. It's not a bad thing, as in the cars they build - little ever goes wrong mechanically.
It's not just the sharp blade, the the whole mechanics of the plane. The wood body (oak) must be absolutely flat. Everything working at a very high level of precision, including the craftsmen hand and eye.
"... and it was after long searching that I found the carpenter's chest, which was indeed a very useful prize to me, and much more valuable than a ship loading of gold." Daniel Defoe, Robinson Crusoe, 1719
