Standard compliance rules generally allow showing the first six and last four digits on a statement or receipt or whatever. That leaves 6 digits, and since you know it has to match the cksum, 1/100,000 odds on straight guess.
You may be able to knock down two more digits if you know which bank and card type (debit, prepaid, etc) it is. The first 6 digits used to encapsulate that data but there’s a transition to 8 now.








I’ve heard that yaoi was more meant for the female audience, and bara for a male audience., but there are probably different interpretations.