TOKYO, June 21 (Reuters) - Japan's Nikkei share average struggled for momentum on Friday as losses in chip-related shares countered gains in value stocks amid a weak yen and higher yields.

The Nikkei was down 0.02% to 38,626.95 by the midday break and on course to fall 0.48% for the week.

"The Nikkei was doing well despite the declines in heavyweight chip-related stocks," said Seiichi Suzuki, chief equity market analyst at Tokai Tokyo Intelligence Laboratory.

"The yen's decline was good for exporters and higher yields pushed value stocks higher."

The dollar pushed to a fresh eight-week top above 159 yen, with the Federal Reserve's patient approach to cutting interest rates contrasting with more dovish stances elsewhere.

Japan's 10-year government bond yield rose 3 basis points to 0.98% in early trade.

Chip-related shares tracked market bellwether Nvidia lower. The S&P 500 and Nasdaq fell on Thursday.

Chip-testing equipment maker Advantest lost 1.92% to become the biggest drag on the Nikkei.

Chip-making equipment maker Tokyo Electron slipped 0.63%. Electronic components maker TDK lost 2.66% to become the biggest percentage loser on the Nikkei.

Value shares rose, with the shipping sector jumping 2.3% to become the top performer among the Tokyo Stock Exchange's 33 industry sub-indexes.

The insurance sector rose 1.91% and railway operators climbed 1.25%.

The broader Topix was up 0.26%, led by a 2.99% rise in insurer Tokio Marine Holdings. The index was set to fall 0.5% for the week.

Heavy machinery maker IHI jumped 6.97% to become the top percentage gainer on the Nikkei.

Of the more than 1,600 stocks traded on the TSE's prime market, 927 shares rose and 655 fell with 64 being flat.

(Reporting by Junko Fujita; Editing by Subhranshu Sahu)