Adds quote, additional context

Jan 23 (Reuters) - The yen jumped suddenly against the dollar on Friday, with traders alert to the prospect of intervention from Tokyo to stem the Japanese currency's slide towards multi-year lows, though analysts' initial view was that the BOJ had not stepped in.

The move was not as dramatic as when the BOJ intervened directly in markets in recent years, but came suddenly -- just as trading in London got underway.

The dollar dropped as low as 157.3 yen JPY= having earlier been as high as 159.2. It was last flat on the day at 158.32.

It was not immediately clear what was behind the move, and whether Japanese authorities had kicked off yen-buying intervention.

Japan's Ministry of Finance (MOF) was not immediately available for comment when contacted by Reuters.

"It's too soon to say if it's intervention," said Chris Scicluna, head of research at Daiwa Capital Markets Europe.

"When they have intervened in the past, we have seen bigger moves," he added, referring to the Japanese authorities.

The yen weakened on Friday during a press conference by Bank of Japan governor Kazuo Ueda after the BOJ held rates steady.

Traders have been wary of intervention by Japanese authorities as the yen has approached 160 per dollar.

NOT THERE YET?

The initial view from analysts was that this was not it.

"I don’t think it's from the BOJ, Mr. Ueda didn’t say anything much on FX intervention," said Hoki Omori, chief desk strategist for rates and FX, at Mizuho, in Tokyo.

"Looks like a tactical move from fast money thinking that hikes will come earlier than expected."

The yen has been under pressure since Sanae Takaichi took over as Japan's prime minister in October, dropping more than 4% on fiscal concerns and hovering near levels that have spurred verbal warnings and intervention fears.

A bond rout has underscored investor nerves about Japan's fiscal position as Takaichi called a snap election for February and promised tax cuts, sending government bond yields to record highs.

The weak yen meanwhile has drawn warnings from Japanese authorities they may intervene directly in markets to stem its slide.

Finance Minister Satsuki Katayama said earlier in January she and U.S. Treasury Secretary Scott Bessent shared concerns over what she called the yen's recent "one-sided depreciation".

Tokyo last spent 5.53 trillion yen ($35.18 billion) in July 2024 intervening to haul the yen away from 38-year lows.

The currency has hovered near the weaker end of the 139-158 per dollar channel in which it has traded in 2025, even as interest rate differentials between the U.S. and Japan have narrowed recently .