(Updates with comment, refreshes prices at 0900 GMT)

By Kevin Buckland and Amanda Cooper

LONDON/TOKYO, March 27 (Reuters) - Global shares rose on

Wednesday, nudged higher by a rally in Japanese stocks as the

yen sagged to its weakest since 1990, while the dollar held

mostly steady in a holiday-shortened week that ends with a key

reading on U.S. inflation.

The yen, which has lost more than 7% in value against the

dollar this year already, weakened to as far as 151.975 to the

dollar, triggering an immediate warning from Japan's finance

minister of "decisive action," a phrase he last used in late

2022, right before monetary authorities intervened to buy the

currency.

The yen has been sliding despite the Bank of Japan's first

interest rate hike for 17 years last week, as traders expect

very gradual tightening and possible delays to long-expected

Federal Reserve easing.

BOJ board member Naoki Tamura reinforced the dovish outlook

regarding further tightening on Wednesday, saying the central

bank should "move slowly but steadily toward policy

normalisation".

The Nikkei closed up 0.9%, although equities trading

elsewhere was more subdued. The MSCI All-World index

was flat on the day, as was Europe's STOXX 600

index. S&P 500 and Nasdaq futures were both up

0.3% on the day.

"It's choppy, directionless trading, and there's a good

reason for that: we've hit that time of the quarter when

rebalancing flows are impacting the market," said Tony Sycamore,

a strategist at IG.

Another reason is that two key events -- the release of the

U.S. Federal Reserve's favoured inflation indicator and public

comments from Fed Chair Jerome Powell -- come on Friday, when

most markets are closed for a holiday, he added.

Inflation data "have not been doing what's expected", and in

the event of a hot reading, "the bumpy road that the Fed has

been talking about suddenly starts to look more like a mountain

trek", Sycamore said.

STRONG DOLLAR

The U.S. dollar index, which measures the currency

against six others, including the yen, was 0.1% higher at

104.39, just below Friday's five-week high of 104.49.

The dollar was last 0.16% stronger at 151.79 yen

"If there's any kind of intervention, it only has a

significant lasting impact if the direction of travel has

already begun to turn," Guy Miller, chief market strategist at

Zurich Insurance Group said.

"We've seen intervention in many countries over the years,

but usually, while that can work in the very short term, you

need to see the currency itself fundamentally change direction,

and then policy intervention can reinforce that or exacerbate

the move," he said.

The euro was flat at $1.0827. Sterling

was steady at $1.2623.

U.S. long-term Treasury yields were stable at

4.23%.

Traders are trying to gauge which of the big central banks -

the Fed, ECB or Bank of England - will be first to cut rates

this year.

Meanwhile, Sweden's Riksbank left interest rates unchanged

but indicated it was likely to start easing monetary policy in

either May or June.

Gold was little changed at around $2,178 an ounce, as

it continued to search for a short-term floor following its

surge to a record $2,222.39 last week.

Cryptocurrency bitcoin eased 0.2% to $69,654.

Oil fell for a second day after a report that crude

stockpiles surged in the U.S., the world's biggest oil user, and

on signs major producers are unlikely to change their output

policy at a technical meeting next week.

Brent crude futures for May fell nearly 1% to $85.42

a barrel. The May contract is set to expire on Thursday and the

more actively traded June contract eased 0.86% to

$84.89.

(Additional reporting by Dhara Ranasinghe in London and Kevin

Buckland in Tokyo; Editing by Muralikumar Anantharaman, Kim

Coghill and Jane Merriman)