KanjiJLPT N1
Hinge

hinge, pivot, door, center of things

Mnemonic

A massive tree stands at the heart of a ward, its ancient trunk carved into the hinge for the great gate. Every crucial decision in the ward pivots around this tree — it is the cardinal axis upon which all authority turns, the living hinge of the entire district.
Additional thoughts
Picture a literal tree trunk hollowed and shaped into a giant door hinge at the ward's main gate. The tree IS the pivotal point — central, indispensable, the thing everything revolves around.
Quick recall
A tree trunk at the center of a ward serves as the pivotal hinge on which everything turns.

Details

The keyword for 枢 is hinge. This kanji refers to a pivotal point or mechanism upon which something turns, much like the hinge of a door. By extension, it conveys the idea of something central or crucial—a linchpin around which important matters revolve. It is commonly seen in words relating to central authority or cardinal importance, such as in the concept of a "privy council" or "cardinal" in religious contexts.
On'yomi
すう、しゅ
Kun'yomi
とぼそ、からくり

Used in vocab