The next shot in the currency war will be fired by...

Frank van den Bergh | E+ | Getty Images

The currency war is getting out of control.

A snapshot of the week so far in central banking:

The Monetary Authorty of Singapore surprised markets Tuesday night with a policy switch to pursue a slower pace of currency appreciation, its main policy tool.

Wednesday afternoon, New Zealand's Reserve Bank kept policy unchanged, but significantly altered its language, saying it expects to see a "further significant depreciation" for the kiwi and that "the exchange rate remains unjustified in terms of current economic conditions."

Hungary's central bank struck a decidedly dovish note, hinting at easier policy ahead.