240mm vs 210mm gyuto: which size should I choose?

Get the 210mm. We only point people to a 240mm when they have about 45cm of usable board, cook in volume, and regularly break down big roasts or whole fish.

On the gyutos we've measured for our product pages, the extra length is real. The 210s have a median edge of 213mm from heel to tip and the 240s 240mm. The 240s are also heavier, 195g against 163g at the median, and a touch taller at the heel, 51mm against 48mm. End to end a 240 runs about 39cm and a 210 about 36cm.

That length buys you a longer stroke. A 240 goes through a big piece of meat in one or two pulls and moves a board of chopped vegetables with less shuffling. It costs you board space and control. On a small board the tip hangs off the edge, and fine work like herbs and shallots feels like more knife than the job needs.