KanjiJLPT N1
Tree Trunk

tree trunk, main part, talent, capability

Mnemonic

Every sunrise, a person walks to the same dry Tree Trunk in the meadow. It has no leaves, no branches — just a massive, weathered core standing firm. The person presses a palm to it, feeling the backbone that once held an entire canopy aloft.
Additional thoughts
Visualize dawn light hitting a lone, dry trunk — thick, solid, unmovable. The person touching it reinforces the idea of something fundamental and supporting. Sunrise + Person + Dry = the essential core structure.
Quick recall
At sunrise, a person touches a dry Tree Trunk — the unshakable backbone of the meadow.

Details

The keyword for 幹 is tree trunk. This kanji refers to the main stem or trunk of a tree, the thick central part from which branches extend. By extension, it also conveys the idea of a core, backbone, or main part of something, such as the essential framework of an organization or system. It carries the sense of being the fundamental, supporting structure upon which everything else depends.
On'yomi
かん
Kun'yomi
みき