Yes Virginia Currency wars can be quite effective (at least for a while)

From Sober Look:

...Below is a chart of the JPY/KRW currency cross - the number of South Korean won per one Japanese yen.

JPY/KRW

As Japan went on its devaluation campaign via monetary easing (see discussion), it's export sector quickly obtained a competitive advantage over its Korean rivals. The markets immediately rewarded Japanese firms with significant outperformance over their Korean counterparts. The two markets, which generally traded in tandem (except for a brief period last spring), have now diverged dramatically.

KOSPI (blue) vs. NIKKEI225 (red)

The impact of yen's depreciation on Japan's industries was swift and potent, creating anxiety among South Korean businesses while encouraging Japan to keep driving the yen lower....MORE