Katayama’s comments make intervention a more serious risk for anyone pushing dollar-yen above 160, especially as the US has now been confirmed as a willing partner. Expect choppy, headline-driven trading around that level, with dealers alert to any reports of rate checks. The underlying pressure on the yen remains, though, as rising Fed hike expectations keep rate differentials in the dollar’s favour. Oil matters too: higher crude prices raise Japan’s import bill and add to selling pressure on the yen, which is partly why Tokyo is bringing forward energy subsidies.---Earlier:US Treasury bought yen in July, its first intervention since 1998, as yen nears 160 again---With the yen back near 160, Katayama is reminding markets that Tokyo and Washington are working together on currencies, and that both have intervened before.Summary:Finance Minister Katayama says she is seeing one-sided, rapid moves in currency marketsShe will communicate with the US Treasury and respond appropriatelyShe says the US and Japan shared a common stance on foreign exchange at their summitShe declined to comment on intervention recordsThe government is bringing forward winter utility subsidies, funded from reserve fundsThe yen is back near 160 per dollar, the level that triggered joint US-Japan intervention in the summerMain article:Japanese Finance Minister Satsuki Katayama stepped up her warnings over the yen’s slide, saying she is seeing one-sided and rapid moves in currency markets and will stay in contact with the US Treasury to respond appropriately. Her comments come as the yen trades back near 160 per dollar, the level that drew joint US-Japan intervention in the summer.Katayama said the US and Japan set out a shared stance on foreign exchange at their summit, signalling that Tokyo sees Washington as aligned on the need to curb disorderly moves. She declined to comment on intervention records. That came shortly after the New York Fed disclosed that the US Treasury bought yen in July, its first yen-buying intervention since 1998, acting alongside Japan’s Ministry of Finance.The wording matters. Japanese officials typically use terms like “one-sided” and “rapid” when their concern is growing. Naming coordination with the US Treasury adds weight, because Washington has now shown it is willing to put its own money behind the yen. Japan’s vice finance minister for international affairs, Atsushi Mimura, gave a similar message on Thursday, warning that it was too early to forget the summer’s intervention.The yen’s renewed weakness reflects a familiar gap. A resilient US economy, stubborn inflation and rising expectations of a Federal Reserve rate hike in December are supporting the dollar. The Bank of Japan, which raised rates in June and September, is widely expected to hike again in December. Until that gap narrows, officials are relying on words, and the threat of action, to slow the yen’s fall.Katayama also said the government has decided to bring forward subsidies for household utility bills this winter, paid for from reserve funds. The move aims to protect households from high energy costs. Elevated oil prices have pushed those costs up, and the weak yen makes them worse, because Japan imports almost all of its energy.For markets, the comments make it riskier for traders to push dollar-yen through 160. With both Tokyo and Washington signalling they are ready to act, the risk of another round of intervention is likely to keep the pair volatile around that level in the weeks before the BOJ’s December meeting. This article was written by Eamonn Sheridan at investinglive.com.