Radical
Old Tree

Mnemonic

A tree has stood in the forest so long that its massive trunk has hollowed out, forming a tunnel straight through its core. Villagers walk through the tunnel daily — it's their shortcut to market. Everyone in town knows this old tree; it was ancient before their grandparents were born.
Additional thoughts
Visualize a colossal, gnarled tree with a person-sized hole through its trunk acting as a tunnel. The older a tree gets, the more its heartwood decays, forming natural tunnels. Age and hollowness go hand in hand.
Quick recall
A tree with a tunnel through its ancient trunk is the village's beloved old tree.

Used in kanji