In Japan, tenants are protected in the sense that owners must compensate them for evicting them against their will, while owners cannot foresee the intended tenure length of prospective tenants. If owners cannot specify the term of a lease, social inefficiency emerges: (i) detached houses owned by individual households remain vacant for a certain period; (ii) alternatively, landlords’ newly constructed apartments, which are free from eviction risk, accommodate a large proportion of tenants; and (iii) the apartments are rebuilt frequently even though they remain viable. If a fixed‐term contract is available, only short‐term tenants choose it, and the information asymmetry is dissolved, realizing social efficiency.