Price difference between Kraken en the Chinese exchanges is now over $10. This means arbitration is exhausted for the moment?
It's at $251 on the Kraken at the moment and 253 on OKcoin. That's not a very big difference considering the Kraken is low volume and a small amount of coins can move its market by a considerable amount. Where did you get your figures from?
BTW, your post is timestamped 21:27 CET, Kraken was at 220.29 ($249.80) and OKcoin at ¥1,598.50 ($257.52), according to bitcoinwisdom.com, a difference of $7.72 -- which makes me wonder, where did you get your figures from?

I was looking at different currency markets to you. I only checked the USD markets without doing the conversions into different currencies. I got my figure directly from the Kraken. There is a spread between $249 and $251 on the Kraken and someone had probably bought when I got my figure.
This is what the Kraken's USD market looks like to me.