noun
key-block print; outline block print
Technical term in woodblock printing and etching: a print made from the key block (the block carrying the main outlines) before color blocks are added.
浮世絵の制作では、まず骨刷りを作ってから色版を重ねる。
In ukiyo-e production, a key-block print is made first, and then color blocks are overlaid.
Compound of 骨 (bone, frame) and 刷り (printing), referring to the 'skeleton' or outline print in multi-block printing.