every one’s different but I immediately think of the bottom left and right corner blockers when I think HHKB. Split BS I just kinda thing of as a general 60% thing (though I’m not much of a historian, don’t know if split BS originated with the HHKB).
Bottom corner blockers did not originate from HHKB though:
https://www.ebay.com/itm/WORKING-1984-Apple-Macintosh-Original-KEYBOARD-Model-M0110-Mac-128K-512K-NICE/114563944146?hash=item1aac8b0ed2:g:CmsAAOSwlOJfzr22