random masonry; uneven stonework; disordered piling
Refers to a style of stone wall construction where stones of irregular shapes and sizes are piled without a regular pattern, often seen in traditional Japanese castle walls and retaining walls.
This castle wall is built in the random masonry style.
A stone wall of uneven stonework is visually beautiful.
Compound of 乱 (ran, 'disordered') and 積み (tsumi, 'piling'), referring to irregular stone stacking.