The Japanese yen traded at levels not seen in about 20 months in a dramatic spike on Friday and threatened to cross a key red line that could trigger intervention.

In afternoon trading in Tokyo, the currency broke through ¥159.44 to the dollar — last reached in January — and went quickly to ¥159.68 before falling back.

If it breaks ¥160 to the dollar, intervention could be triggered. If it breaks ¥161.95 to the dollar — reached in early July 2024 — it would be at its weakest level in 39 years.

The yen lost ground against the dollar as oil prices soared after Israel and the United States attacked Iran in late February.

Many investors and analysts see ¥160 to the dollar as the point that would force Japan’s hand and leave it with no choice but to sell dollars and start buying yen to support its currency.

“It is true that significant volatility has emerged in financial markets, including in foreign exchange, following the situation in the Middle East,” Finance Minister Satsuki Katayama said Friday.

“In light of these major market fluctuations — particularly the surge in crude oil prices — we are mindful of the impact exchange-rate movements could have on people’s daily lives and are maintaining a stance of taking every possible measure to ensure full preparedness at all times.”

Japan and the U.S. agreed in a statement last year that currency intervention is “reserved for combating excess volatility and disorderly movements in exchange rates.”

“In any case, we remain in very close contact with the U.S. authorities on a regular basis,” Katayama added.

Japan last stepped into the currency market in July 2024, buying ¥5.5 trillion over two days after the currency tumbled toward ¥162 against the dollar — its weakest level since 1986.

That move briefly lifted the yen to the ¥157 range, and the yen kept strengthening until October that year.