Korean and Japanese foreign exchange authorities sold dollars on the night of the 30th to slow the pace of currency depreciation, according to reports on the 31st. As a result, the won and the yen both plunged against the U.S. dollar. In the foreign exchange market, some said it was as if the two countries mounted a joint operation to drag down exchange rates together.
The won-dollar rate fell from 1,437.4 won at 3:30 p.m. the previous day to 1,419 won at 10:44 p.m. It declined to 1,418 won as of 6 a.m. It is currently in the 1,430-won range in transaction.
The yen-dollar rate also fell from the upper 163-yen range in the afternoon the previous day to the upper 157-yen range overnight. It is now moving in the 160-yen range.
Nihon Keizai Shimbun reported that the Japanese government and the Bank of Japan intervened in the market by buying yen and selling dollars. Korea's foreign exchange authorities were also said to have intervened around the same time by buying won and selling dollars.
At the time when the won and yen exchange rates plunged, the United States also provided back-end support by conducting a "rate check (exchange rate check)"—inquiring about transaction rates with foreign exchange market participants. When foreign exchange authorities conduct a rate check, market participants judge that the likelihood of future intervention is high.
Earlier, Korean and Japanese foreign exchange officials said they would continue cooperation related to the foreign exchange market. On the 8th, at the opening ceremony of the Korea Investment Corporation (KIC) Tokyo branch, Mimura Atsushi of Japan's Ministry of Finance said, "Because the two countries have similar economic and trade structures, movements in financial markets at times show similar patterns," adding, "We are in particularly close contact with our Korean counterparts on recent market trends, including the foreign exchange market, and we will continue this cooperation going forward." On the same day, Moon Ji-seong, Deputy Minister for international economic management at the Ministry of Economy and Finance, also said, "Korea and Japan are communicating closely and staying in frequent contact."