(Updates with details, share prices and context)

By Satoshi Sugiyama

TOKYO, June 23 (Reuters) - Japan's Nikkei share average fell

to a one-week low on Tuesday, retreating after a strong rally

that had driven the index to successive record highs, prompting

investors to lock in profits.

The Nikkei dropped 3.6% to 69,788.38, hitting a

one-week low and closing below the 70,000 mark for the first

time since last Wednesday.

The broader Topix slipped 2.6% to 3,990.38.

The pullback follows a powerful rally driven by sustained

buying in AI and semiconductor stocks, which pushed the Nikkei

past 72,000 for the first time on Monday, just two sessions

after it breached 71,000.

"After a string of gains, the market appears to be seeing

some mild profit-taking," said Masahiro Ichikawa, chief market

strategist at Sumitomo Mitsui DS Asset Management.

Market breadth remained weak,with 184 decliners in the

Nikkei 225 against 41 advancers.

AI-related shares, which have powered the market's recent

surge, led losses ahead of Micron Technology's ( MU ) earnings

announcement. Memory chipmaker Kioxia ( KXHCF ) slumped 15.1%

while tech investment giant SoftBank Group sank 10.1%.

Shares of cable and optical fibre maker Fujikura ( FKURF )

climbed 5.3%.

Among other notable losers, cable and components maker

Furukawa Electric ( FUWAF ) fell 15.5%, while non-ferrous metals

producer Mitsui Kinzoku ( XZJCF ) lost 12.6%.

Defensive names saw some gains, with dairy and confectionery

maker Meiji Holdings ( MEJHF ) rising 3.5% and logistics company

Nichirei ( NCHEF ) adding 3.1%.

Technical indicators had signalled overheating, with the

Nikkei's 14-day relative strength index at 73 on Monday, above

the 70 level that suggests overbought conditions, before easing

to 61.1 on Tuesday.

"The market had already been looking overheated for quite a

while as richly valued names kept rising, so it would not have

been surprising to see a correction at any time," Ichikawa said.

"Today, the selling appeared to pile up."