With some of the knives, the spine thickness doesn't tell the whole story! Many that are forged are much thicker out of the handle, and narrow down pretty fast to the heel area. Shibata are crazy thin lasers and cut really well, but may be more fragile and easier to chip if you aren't used to them. The Tabata looks pretty thin behind the edge from the few choil shots I have seen and more robust above the thin edge (toward the spine), so it would be beefier overall but still should perform pretty well. Either looks like they would perform well, so it's more of a preference if you like thin lasers or workhorse/work pony type knives!