KanjiJLPT N1
Ditch

ditch, moat, canal

Mnemonic

The earth around the castle must yield — soldiers hack at the ground with pickaxes, forcing it to give way scoop after scoop. Slowly a massive ditch encircles the fortress, dark water flooding in to keep every invader at bay.
Additional thoughts
Picture samurai commanding workers to make the earth yield, carving a deep moat. The earth resists, then yields, and the ditch fills with murky water. Earth + Yield = Ditch.
Quick recall
Earth forced to yield becomes a castle's protective ditch.

Details

The keyword for 堀 is ditch. This kanji refers to a man-made channel or moat dug into the earth, often used for drainage, irrigation, or as a defensive feature around castles and fortifications. In Japanese history, moats surrounding castles were a critical element of military architecture, and this kanji frequently appears in place names and surnames associated with such features.
On'yomi
くつ
Kun'yomi
ほり