I am just playing around with a few things. If you have a moment and a ruler (or a caliper), could you have a look at your 210 to 270 wa gyuto(s) and let me know the size of the tang at the point where it enters into the handle? Something like 4mm x 12mm (or whatever that is in inches ). I am hoping to get a list for a few makers together to get a better idea of the sizes. Of course, they will vary a bit even for each maker, but a general idea is enough for now.