TOKYO, May 20 (Reuters) - Benchmark Japanese government

bond yields climbed to the highest in more than a decade on

Monday, helped by a rise in U.S. yields, and continuing a

gradual grind higher amid expectations of tighter domestic

monetary policy this year.

The 10-year JGB yield rose 3 basis points

(bps) to 0.975%, a level not seen since May 2013, in the very

early days of former Bank of Japan Governor Haruhiko Kuroda's

unprecedented policy-easing experiment.

The benchmark yield has climbed 25 bps since the end of

March, when current BOJ Governor Kazuo Ueda lifted interest

rates for the first time since 2007, amid growing speculation he

will continue to phase out those policies in coming months.

Ueda suddenly adopted a more hawkish tone two weeks ago, as

the weakest yen in 34 years risked derailing a virtuous cycle of

mild inflation supporting higher wages.

The extent to which inflation expectations have jumped amid

the currency's slide was clear in Monday's "way stronger than

expected" auction of inflation-linked 10-year JGBs, said Shoki

Omori, chief Japan desk strategist at Mizuho Securities.

"If inflation expectations are strong, rates expectations

for nominal JGBs should increase as well," Omori said. "JGB

yields across the curve are going to increase, implying that the

10-year yield can go above 1% any time."

JGB yields were also pulled higher by a climb in Treasury

yields from Friday, as Federal Reserve officials sent cautious

signals about the speed of U.S. rate cuts. The 10-year Treasury

yield last stood around 4.412%.

The gaping U.S.-Japan yield differential has kept the yen

depressed despite the opposing paths for monetary policy.

Following a meeting with Prime Minister Fumio Kishida on May

7, Ueda said the BOJ will be "vigilant" to yen moves in setting

policy. A day later, he said the BOJ may raise rates if the

currency's drop affects prices significantly.

The central bank then surprised markets a week ago by

cutting the amount of JGBs it offered to purchase in a regular

buying operation, sparking bets that quantitative tightening may

not be far off.

Superlong JGB yields marked fresh decade peaks on Monday,

with the 20-year yield rising 2.5 bps to 1.780%

for the first time since June 2013, and the 30-year yield

climbing 3.5 bps to 2.085% for the first time

since July 2011.

The five-year yield rose 2.5 bps to 0.570%,

the highest since March 2011. The two-year yield

added 1 bp to 0.34%.