The depreciation of the currency of a country many times make other currency become stronger.This happens with the relation between the yen and the dollar, both currencies are favored when some of them suffers a change.
After the crisis that suffered Japan during the Second World War, the Asian country stayed in a situation of extreme poverty, after some time it was able to recovery from this adverse scenario and became one of the strongest economies in the world, as a currency as the yen that supports it.
There is an old African proverb that says that when “the elephants fight, the one that suffers is the grass”. This is what happends frequently when there are changes on the exchange rates, or a currency become stronger, there are nations that are favored and others that suffered their consequences. The yen and the dollar are the two sides of the same coin, on the one hand the currency of the northern country has falled, while the yen has increased its value abruptly.
In the exchange yen and dollar, the devaluation of the American currency has favored the American companies that export product abroad and are bought by the nations that see the advantage on the devaluation of the dollar. The appreciation of the yen has been against the interests of the Asian countries as their debts and imports are in the most cases from Japan. This situation provoked the claims of many Asian countries that asked the Japanese government to have less debt payment conditions in yen nominal value to compensate partly the difficulties that they should face since the increase of the yen value, and Japan refused it.
The decision of strengthen a currency and devalue the other has its origins in the economic politic that wants to follows the government of the moment. The yen and the dollar are in an extreme competence system, and so the depreciation of a currency is considered an instrument that is useful to reduce the costs of the exports of a country and be efficient to penetrate at the foreign markets.