Part of this is because it's leaping up the Japanese top grossing charts.
The game was updated on 17 June with support for the Japanese language.
This came on top of a cross promotion with Puzzle & Dragons - Japan's top grossing iOS game during 2013.
The end result has been a tripling of revenue.
Tokyo riser
As Distimo says 'During the first six days of July, Clash of Clans already generated 61% of the total revenue it generated in June in Japan'.
It will be interesting to see what impact this has on Clash of Clans' global iOS revenue ranking when it's had a full month of revenue.

During June 2013, it was the #2 top grossing iOS game globally, just beaten by King's Candy Crush Saga.
[source: Distimo]