TOKYO, June 19 (Reuters) - Japan's Nikkei share average

rose during the morning session on Wednesday, with technology

shares rallying as the market reacted favourably to U.S.

semiconductor stocks' gains overnight.

U.S. chip star Nvidia ( NVDA ) overtook Microsoft ( MSFT )

to become the world's most valuable company, ending the day with

a market capitalization of $3.22 trillion. The Philadelphia

Semiconductor index climbed more than 1%.

The news supported Japan's tech-related shares, which helped

lift the Nikkei by 0.58% to 38707.21 by the midday

break. The index was on track for a second straight day of

gains.

The broader Topix gained 0.72% at 2735.19.

"There were some concerns last week about political risk in

Europe and the Nikkei also declined. But since the beginning of

this week, U.S. and European shares have steadied, and Nvidia ( NVDA )

performed strongly," said Masahiro Ichikawa, chief market

strategist at Sumitomo Mitsui DS Asset Management.

The combination has improved sentiment, he said.

Trading volumes were low on Wednesday, however, limiting

large moves in stocks.

Investors were also waiting for the Bank of Japan's specific

plans regarding the pace and size of tapering, which the central

bank said it would announce at its July monetary policy meeting.

"Since we don't know the details yet, it's difficult to

predict how yields will react," said Ichikawa.

Rising yields tend to weigh on growth stocks since higher

rates offer investors less risk while also making borrowing to

fuel growth more expensive.

In individual stocks, AI-focused startup investor SoftBank

Group gained 2.9% while chip-testing equipment maker

Advantest ( ADTTF ), which counts Nvidia ( NVDA ) among its customers,

climbed 3.5%.

Together, the two shares added around 108 points to the

Nikkei.

Electronic parts maker TDK was up 3%.

Mitsubishi Motors ( MMTOF ) jumped 9.2% to top percentage

gainers. The auto firm's president indicated in an interview

with the Nikkei newspaper that the company may buy back shares

for the first time in 18 years and increase shareholder returns

in fiscal year 2025.