Credit Card use .. 2 swipes?

Just out of curiosity, I'd like to ask why do the sales clerk ask whether you'd liked to have your credit card swiped once or twice when conducting a transaction?

I wanted to ask this question for a long time now. Thank alot.

They're actually asking you how many installments you would like to break down the payment into. Japanese credit cards must be paid in full at the end of each month. But at the time of purchase you are allowed to specify how many months you'd like the charge to be spread out over at a small service fee that depends on the number of payments you choose. Don't worry about this if you use foreign cards though as the system doesn't allow foreign card charges to be broken down into installments. Requesting more than one charge will cause the transaction to be declined.

I bet what you heard was something like: "ikkai barai desu ka, nikai barai desu ka" kind of thing. Yes, they are asking you if you want to pay in "single installment/payment" or "two installments/payments." :)

Some Japanese card companies offer two-installments payments without any additional fee (or pay in single payment but at a subsequent bonus season).

Oh now I see what that one cashier at Osaka was asking from me! I payed with my VISA (not japanese card) and the person kept asking me something over and over again, I could only say "wakarimasen" because I got no idea that this kind of method is in use. We were both getting very frustrated because of the huge line after me and due to lack of communications, somehow I managed to pay when I just repeated the sentence she was saying hehe. Strange though if it offers that option with foreign cards too? Well now I know to say ikkai if I hear something like that.

A lot of Japanese shop staff won't be aware that with foreign credit cards only "Ikkai barai" is possible, so they ask anyway, because that is what they have been trained to do when the customer pays by credit card.