If I had to choose one between what I have and owned (180 Heiji, 180 Toyama, 165 Yoshikane, 150 Watanabe, 150 Shigefusa and 150 Konosuke) I'd keep the 180 Toyama with a burnt chestnut handle...good balance, knuckle clearance, sharpens nicely and versatile length. The Heiji is always in my kit as well since I use it for other things and I like the steel better but the heel is too low for extended sessions. The Wat and Kono were thiner which was nice for squab and smaller birds but the Kono was double bevel. The Shig is just sexy but smaller than I like. I tend to prefer a traditional single bevel, thicker spine, wa handle and carbon all the way.
They're fun little knives that sharpen easily but not necessary. My lead prep cook smokes me speed and precision wise with his curved Victorinox 5.6606.15. I let him use my knives whenever he wants but he still prefers a boning knife over a garasuki and a sujihiki over a deba for breaking down salmon...he uses deba for all other fish though.
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