the Government of Japan, Civil Code (Japanese: 民法 Minpō… (2006)
“ A person who has become a guarantor against the will of the principal obligor shall have the right to obtain reimbursement only to the extent that the principal obligor is actually enriched. In such case, if the principal obligor asserts that he/she had, prior to the day of the demand for reimbursement, grounds for set-off against the obligee, the guarantor may demand that the obligee perform the obligation which would have been extinguished by operation of such set-off. ”
