I say, and with God's success: If the price is in cash, then possession is achieved by actual delivery or by freeing it. If the price is a check, possession is achieved by receiving the bank check — any check issued by the bank that commits to paying its value to the bearer — and the certified check — that is, the check for which the bank has reserved its value from the account of the issuer for the bearer — unlike the personal check; due to the lack of obligation from the bank to pay its value to the bearer, as its value may not be available in the account of the issuer, so possession is not achieved by withdrawing its value from the bank. Therefore, various currency contracts are permissible with the bank check and the certified check, unlike the personal check; due to the lack of possession. Our Sheikh has presented forms of possession in checks in the jurisprudence of sales (2: 393-402), but what I have mentioned is sufficient, and God knows best.