Bought this on Kappabashi street in Tokyo years ago. Been misusing it as my main knife for quite a while. I need to move up to a proper knife (ow my knuckles). The blade is 240mm long, and about 40-42 deep. Approximately 2mm at the spine (can't find my calipers at the moment). I don't even know what type of knife this is, much less what the chop says. Any info you can provide would be super useful.