He quickly got the hang of it.
noun
cremated remains; ashes (esp. bones)
Only when written 骨
Refers to the bone fragments collected after cremation. Used in funerary contexts.
遺族は骨を拾って骨壺に納めた。
The bereaved family picked up the bones and placed them in the urn.
The common word for 'bone' in everyday contexts. コツ/こつ is a Sino-Japanese reading used mainly in compounds or the 'knack' sense.
From the Sino-Japanese reading of 骨 (bone). The 'knack' sense likely developed from the idea of 'getting to the bone' or essence of a skill.