KanjiJLPT N1
Patrol

patrol, go around, circumference

Mnemonic

A guard's path follows a winding river — its curves create a perfect patrol route. Each bend in the river marks a checkpoint, and the flowing water reminds him: never stop, keep circling. The river carved the path, and now the path serves the patrol.
Additional thoughts
Picture a river's snaking shape (巛) inside the path radical (⻌). The river's natural loops become a guard's circuit. Water never stops flowing; a patrolman never stops walking his rounds.
Quick recall
A path tracing a river's bends forms a natural patrol circuit.

Details

The keyword for 巡 is patrol. This kanji conveys the idea of going around an area in a systematic manner, making rounds to inspect or watch over a place. It carries the sense of circulating through a route or territory, as one would when making regular tours of duty. The character broadly encompasses the concepts of making rounds, touring, and moving through a circuit in an orderly fashion.
On'yomi
じゅん
Kun'yomi
めぐ.る、めぐ.り