(Updates with closing levels)

By Kevin Buckland

TOKYO, June 27 (Reuters) - Japan's Nikkei share average

fell on Thursday, giving up much of its gains from the previous

session, as the yen's slide past the closely watched 160 per

dollar level put traders on high alert for intervention.

The Nikkei closed down 0.82% at 39,341.54.

Technology shares underperformed to drag on the

benchmark index after a sell-off in U.S. chipmaker Micron

Technology ( MU ) in after-hours trading soured the mood.

The broader Topix slid 0.33% to 2793.70, with a

sub-index of growth shares sliding 0.6%, compared with

a 0.08% decline for value shares.

Risk events loom for investors in all asset classes,

including a U.S. presidential debate later in the day, and the

release of the Federal Reserve's preferred inflation gauge on

Friday.

The yen was last at 160.36 per dollar, after

touching 160.88 overnight for the first time in 38 years. A

plunge to 160.245 in late April triggered an official Japanese

currency intervention worth about 9.8 trillion yen ($61.08

billion).

The proximity to the quarter-end may also be influencing

markets. The Nikkei saw a three-day run of increasingly strong

advances, culminating in Wednesday's 1.26% surge.

"The size of yesterday's Nikkei gains were very surprising,

and I don't expect it's just me who thinks that (way)," said

Kazuo Kamitani, an equity strategist at Nomura Securities,

adding that the large volume suggested it was the work of

overseas funds or securities dealers.

The technical test for the Nikkei now is whether it can

reclaim the May 20 high of 39,437 by the end of the week, he

said.

"If not, yesterday's rally will likely have been just an

anomaly," he added.

In individual stocks, chip-making equipment heavyweight

Tokyo Electron ( TOELF ) slid 2.4% to become the biggest weight

on the Nikkei, followed by Uniqlo parent company Fast Retailing ( FRCOF )

, down nearly 2%.

At the bottom of percentage losers was chip-related firm

Screen Holdings ( DINRF ), which tumbled 5.7%.

($1 = 160.4400 yen)