The Tokyo Metropolitan Government says it confirmed 729 new cases of the coronavirus in the capital on Thursday.

This is the first time since February 4 that the daily tally has topped 700 in Tokyo.

A Japanese research institute predicts that the UK variant of the coronavirus will account for more than 80 percent of cases in Tokyo and its surrounding areas by early May.

The National Institute of Infectious Diseases made the prediction on Tuesday based on the results of tests for coronavirus variants.

Japanese Prime Minister Suga Yoshihide will leave Tokyo late Thursday for Washington, where he will hold a summit meeting with US President Joe Biden.

This will be Suga's first visit to the US since he became prime minister last September. Suga will also be the first foreign leader Biden will meet in person since he took office in January.

The Japanese government is seeking support for its plan to release treated water from the crippled Fukushima Daiichi nuclear power plant into the ocean. The water will be diluted before its release so it meets global safety levels.

Industry minister Kajiyama Hiroshi spoke online with the head of the International Atomic Energy Agency on Wednesday, a day after the Japanese government officially made its decision.

Japan's nuclear regulator has decided on Wednesday to publicly disclose its audit on the capabilities and soundness of the facility to be built for diluting treated water from the crippled Fukushima Daiichi nuclear power plant before releasing it into the ocean.

This follows the government's decision on Tuesday to approve the release of the treated water from the plant.

Surveys by local governments in Japan show the coronavirus variant first detected in Britain is surging in the country. The variant, dubbed N501Y, is said to be more transmissible than the original coronavirus.

In Osaka Prefecture, a survey of 304 people who tested positive in the week through April 3 showed 73.7 percent, or 224, with the variant.

The head of the Japanese government's advisory panel on the coronavirus says the latest surge in infections in Japan can be described as a fourth wave.

Omi Shigeru spoke about the issue on Wednesday at a Diet committee meeting.

The Tokyo Metropolitan Government confirmed 591 new coronavirus cases in the capital on Wednesday.

The figure is the highest since the second state of emergency was lifted last month.

An approximately 400-year-old stone wall from former Edo Castle has been found on the premises of the Imperial Palace in central Tokyo.

The wall was unveiled to the media on Tuesday. It was discovered as excavation work was being carried out in the palace's eastern garden ahead of the planned rebuilding of an Imperial repository.

In Japan, the government has officially decided to release treated water from the crippled Fukushima Daiichi nuclear power plant into the ocean.

Before that happens, the water will be diluted so the concentration of contaminants meets global safety levels.

Japan's western prefecture of Osaka has broken another daily record. It reported over 1,000 new coronavirus cases on Tuesday, marking a four-digit count for the first time.

Authorities confirmed 1,099 new cases, a rapid surge from only 38 cases about a month ago.

The foreign and defense ministers of Japan and Germany have agreed to strengthen bilateral ties in security cooperation and shared concerns about China's recent activities.

The ministers held "two-plus-two" talks in a teleconference format on Tuesday.

The Olympic torch relay leg in Osaka Prefecture, western Japan, started on Tuesday away from public roads in a closed park course to prevent a further spread of the coronavirus.

The event was originally scheduled to take place on public roads. It is instead being held on an approximately 3-kilometer route around the iconic Tower of the Sun at the Expo '70 Commemorative Park in Suita City.

Osaka Prefecture confirmed 1,099 new cases of the coronavirus on Tuesday. That's a record high for the western Japanese prefecture.

It is also the first time that the daily count surpassed 1,000 in the prefecture.