[Assessed 98.1%] Detached house in Tokorozawa City, Saitama — 15 min from Higashi-Tokorozawa Sta.

Shimoyasumatsu is published only to the oaza level, with no lot number, so we triangulated the site from the two stations given in the listing (Higashi-Tokorozawa, 15 minutes on foot; Kiyose, 24 minutes). Against 2.78 km between the stations, walking distances of 1.2 km and 1.92 km fall almost in a straight line, placing the solution near longitude 139.509-139.513 and latitude 35.787. The other solution lies across the Yanase River in Kiyose City, outside Oaza Shimoyasumatsu, so we discarded it.

We geocoded the lot annotations 1161 and 1170 printed on sheet 34091 through the Geospatial Information Authority address API, and confirmed that the measured page coordinates matched the value back-calculated from the scale to within 6 points (about 10 m) before reading the sheet. Calibration used only lot annotations on the same sheet; we did not extrapolate across sheet numbers. Around the estimated position the local streets are uniformly 120D and only the diagonal arterial is 135D, so we took the modal 120,000 yen per sqm. It matches the figure we measured in the same oaza on 1 September 2026.

Street values touching Oaza Shimoyasumatsu on sheet 34091 range from 110D to 135D. The lowest, 110D, still gives 91.9 per cent; the highest, 135D, gives 101.4 per cent. Sheet 34090 to the west carries a multiplier zone and the Shimoyasumatsu-Higashi land readjustment area (individually assessed), where the lowest published figure is 105D — even that yields 90.1 per cent. Errors in the position estimate do not change the conclusion.

We opened five images: two exteriors, the floor plan, a wide shot including the frontage road, and a 3x enlargement of the right-hand boundary. The road is a paved residential street, and the concrete apron runs to it without a step. The eastern boundary carries only a single course of concrete block (one standard unit, 20 cm high) with mesh fencing, and the neighbouring ground sits at much the same level, so the retaining height is about 0.2 m. We found no retaining wall, slope, sloping ground or stepped approach, and the plot is not a flag lot.

Kenbiya states in its guide to listings that land areas are given net of any private-road burden, so we did not deduct again. The remarks give the measurement method as surveyed. There is no mention of a private-road burden, sloping portion or flag-lot pole, and the photographs show a regular plot fronting the road directly with no pole. We therefore used the published 158.13 sqm as the effective land area.

Completed in May 2026, the building is nought years old, so none of the 22-year statutory life for timber construction has yet been depreciated. The full 220,000 yen per sqm x 95.64 sqm = 21,040,800 yen sits in the valuation, which is 53 per cent of the total. Because the building carries that much weight, the assessed ratio will fall faster with age than on a land-heavy property.