TOKYO, May 28 (Reuters) - Japan's Nikkei share average

rose on Wednesday, setting the benchmark index on course for a

fourth straight session of gains, with a sharply weaker yen

buoying the bourse's heavyweight exporters.

Semiconductor-related shares also got a boost from an

overnight rally in their U.S. peers, ahead of earnings from

artificial intelligence chip leader Nvidia ( NVDA ) later on

Wednesday.

The Nikkei added 0.5% to 37,918.86 by the midday

recess. It rose to as high as 38,178.73 at one point, but

struggled to stay above the psychological 38,000 line.

The broader Topix also advanced 0.5%.

While a weaker safe-haven yen amid an improvement in overall

market sentiment globally supported the Nikkei in the latest

session, "one can't say the foreign-exchange market has

stabilized," said Masahiro Ichikawa, chief market strategist at

Sumitomo Mitsui DS Asset Management.

Some additional push is needed to take the Nikkei firmly

above 38,000, such as further positive developments in U.S.

tariff negotiations, he said.

Tech was the top performing Nikkei sector, with chip-testing

equipment maker and Nvidia ( NVDA ) supplier Advantest ( ADTTF ) the

biggest gainer in index-point terms, followed by chip-making

machinery manufacturer Tokyo Electron ( TOELF ).

Advantest ( ADTTF ) jumped 2.1%, accounting for 39 points in the

Nikkei's 195-point rise, while Tokyo Electron ( TOELF ) contributed 14

points.

Overnight, the Philadelphia SE semiconductor index

rose 3.4%, outperforming a 2% gain for the S&P 500.

Automakers also saw solid gains with the yen

trading at around 144.30 per dollar, down from a one-month peak

reached on Tuesday. A weaker yen boosts the value of overseas

revenues.

Toyota ( TM ) rose 0.4%, and Honda ( HMC ) jumped 1.7%.

Electronics exporters also benefited, with Sony ( SONY )

advancing 1.3% and Nintendo ( NTDOF ) up 1.6%.

(Reporting by Kevin Buckland; Editing by Varun H K)