Toshi-keikaku-zei (city-planning tax)

Toshi-keikaku-zei is a supplementary annual tax that funds local infrastructure, charged on property located inside a designated urbanization zone — which covers essentially all of central Tokyo and the 23 wards. The cap rate is 0.3% of assessed value, and in practice it arrives on the same bill as fixed-asset tax (kotei-shisanzei), so most owners think of the two as one combined property tax payment. Like the property tax, it's pro-rated between buyer and seller at settlement based on the January 1 ownership date. Small in absolute terms, but include it so your holding-cost math is honest.