For right now, we advise that you go to the withdrawal page page for a given fiat currency to see if you can withdraw it, rather than assuming you can withdraw it because you are allowed to trade it.
Wow, this is a strong statement! The comparison to an exchange with no withdraw option is a casino where you are not allowed to cash out winnings; or a restaurant where the food comes in a transparent but locked glass box allowing you to have a look but not a taste.
Since you do such a great job at kraken, it really did not come to my mind to check the withdrawal page before trading. It is the curse of your good reputation that I now blame you for my trouble, which was caused by the combination of kraken doing a bad job here and me having (blind) trust in kraken because of its awesome jobs all the time before.
It is my understanding that -- given kraken's ambition to nor only become world's leading exchange but also reshape the whole financial system -- it is necessary to iron out effects of mistakes kraken takes part in. In this case, I refer to an exchange of my JPY funds at market rate to a different currency. It would show that you care for your customers and take responsibility for your growth pains. It does not come at at any cost to you, since you have the banking relations.
ICFielder - I think we have miscommunicated, because my point was merely that, as our system currently works, it will allow you to trade in currencies that you can't withdraw and the best way to avoid this is to look at your withdrawal page before you trade. This is just a fact about how our site currently works - we recognize that it isn't ideal and are working on a solution to address it. It's perfectly natural to assume that you are able to withdraw a currency you are able to trade, so I didn't mean to suggest in any way that it was a poor assumption on your part (if you took me to be saying that).
As for your particular JPY trade, I believe you have a support request open for it, so let's talk through the ticket and work on a solution for you.