The yen rose sharply to a four-month high against the U.S. dollar, while the Nikkei stock index plunged to a two-month low on Tuesday as market participants were surprised by a Bank of Japan decision that they saw as monetary tightening following a decade of its ultraloose policy under the current governor.The Japanese currency strengthened by around 5 yen versus the dollar to trade at the 132 level, its highest since August, and the Nikkei briefly fell nearly 3 percent, after the central bank decided to allow long-term government bond yields to trade in a wider range.The 225-issue Nikkei S…READ FULL ARTICLE