TOKYO, Oct 6 (Reuters) - Japanese stocks inched up on Tuesday, as risk sentiment improved after U.S. President Donald Trump returned to the White House following treatment at the hospital for COVID-19, easing fears over political uncertainty.

The benchmark Nikkei share average rose 0.37% to 23,399.44 points by the midday break, while the broader Topix gained 0.25% to 1,641.37.

Nearly two-thirds of 33 sector sub-indexes on the Tokyo exchange traded higher, with insurance, oil and coal products and rubber products leading the advancers on the main bourse.

Investors took cues from Wall Street's positive finish overnight when main indexes rose sharply on stimulus hopes and on news President Trump would return to the White House after a three-night hospital stay.

Trump's doctors told reporters the president has not had a fever in more than 72 hours and his oxygen levels are normal, but they declined to discuss any toll the disease could have on Trump's lungs or disclose when he last tested negative for the coronavirus.

In Japan, technology and semiconductor shares gained as they benefited from more than a 2% rise in the U.S. Nasdaq overnight.

SoftBank Group gained 2.22% while Screen Holdings rose 1.42%.

Stocks that outperformed included Hino Motors Ltd, which jumped around 5% after Toyota Motor Corp < 7203.T> said on Monday they would jointly develop a heavy-duty fuel cell electric truck for the North American market.

Japan Exchange Group Inc, the owner of the Tokyo Stock Exchange, dropped more than 2.7% after the exchange appointed four external board members to a committee to investigate last week's trading outage.

System developer Fujitsu Ltd, also edged 0.25% lower as it continues to examine the cause of the incident.

Elsewhere, the Mothers Index of start-up firm shares rose 0.77%. (Reporting by Eimi Yamamitsu, Editing by Sherry Jacob-Phillips)