カン, ケン, ま.く, まき, ま.き
scroll, volume, book, part, roll up, wind up, tie, coil, counter for texts (or book scrolls)
JLPT2 G6 S9 F944
As per ?# as described in 券 (wrap/roll up) + a bending figure → *curl*; *roll*; *roll up*; *reel*; *coil*; *wind* (up/around) → *volume* (of a set of *books*, originally, rolled *scrolls*).
[Full Kanji Etymology List]