I wonder about the accuracy of these measurements. It ain't easy to measure things so small!

(in this post um is micrometer. I don't have a mu on my keyboard).

First, the micrometer being used. Most of the Mitutoyo micrometers, even the most expensive digital ones with a 0.001 mm resolution have an accuracy specification of +/- 1 um or worse. So the fabled 2 um shaving could be somewhere between 1 and 3 um or worse.

Then you have the handling errors. Temperature must be controlled very carefully. Just holding the micrometer in your hands for a few minutes creates errors of several um's. Holding it upside down or horizontal, has influence too

And then about the measured shaving itself. Humidity has a direct effect on the thickness of the shaving. Imagine a hall full of people, the difference between the early hours and later in the afternoon? I don't know how large the effect is, but it could be substantial. Think also about dust. Planing is a dust creating exercise, so things need to be cleaned carefully before any measurement.

When the competition is fierce, winners and losers divided by a mere um, then the measurement technique becomes very important. And I think it is even harder to compare the results from one competition to the next.

I would presume this is a hotly debated subject on Japanese planing contest forums! (if such things exist).