The walls are built from round river stones. Iriki Fumoto follows the Kiyoshiki River, and along its lanes run tamaishi walls — stacked cobbles taken from the riverbed — with hedges above them. Stones without corners are difficult to build with, because nothing sits square and every piece has to be chosen for how it will engage with its neighbours, so the competence of the mason shows up directly in how long the wall stands.

At the former Masuda residence the gate and the main house both survive, and the arrangement worth attention is the distance held between them: how far you walk after passing through the gate before reaching the entrance, and what the household intended you to see while doing it. Iriki Fumoto was designated an Important Preservation District in December 2003. The surrounding country is given over to field crops and livestock, and a good many of the households along these lanes are still farming households. Sendai's town centre is about thirty minutes away by car and Kagoshima city about an hour, so daily life here assumes a vehicle.

A town beside a river takes its materials from the river. Quarrying stone in the hills and carrying it down is slower than picking cobbles out of the bed in front of you, so the form of a wall is determined by what happened to be lying about locally rather than by any preference for one look over another. The masons worked with what the water had already rounded for them, over a period considerably longer than the town has existed. In that sense the walls of Iriki were made by the Kiyoshiki River, and the men who built them only did the stacking.