The Moritaka Supreme Series is not B#1; it is Blue Super, like the Richmonds. The Kohetsu & ASLaser are stainless-clad while the Moritaka is reactive iron-clad. Blue Super is premium steel that is typically heat treated to higher hardness, and as such exhibits great edge retention. Edge potential is going to be so close on all the whites & blues it's sort of moot, but the AS will definitely take more time on the stones.
You are going to have a hard time finding a monosteel B#1.
Your not going to get much thinner than the Kohetsu, and it is a really great knife. My earlier comment about the Blue Super taking longer on the stones applies slightly less to the Kohetsu 210 because it's SO thin on the edge... just not much steel there to grind. It's a fun knife to use with an upswept spine & smooth radius profile.
@Hrc65, the Moritaka takes a really scary edge, but I've found if you bring it to that extreme you have to be vigilant in your knife handling as it's brittle nature must not be ignored. The Mori is a stiff knife with a rustic aesthetic. I enjoy their knives a lot, and they are the thickest of these 3 mentioned.
is a lower price point Blue#1 @CKTG, and it is iron-clad.
is a rare monosteel B#2.
An interesting Blue#1, albeit iron-clad, is the MURATA BUHO<--link
. It has an asymmetric semi-concave grind that I liken to a single bevel w/o the steering issues.