An American Marine readies to land on Guadalcanal during the five-month struggle for the island between late 1942 and early 1943. Three thousand miles south of Tokyo, Guadalcanal was a major shipping point for military supplies. The Allied victory there in February, 1943, marked a major turning point in the war after a string of Japanese victories in the Pacific. (Photo by Joe Scherschel/Time & Life Pictures)

A humpead wrasse, transported from Japan's southern island of Okinawa, swims with other tropical saltwater fish on display in a tank for the Sony Aquarium 2017 exhibition in Tokyo on July 31, 2017. The Sony Aquarium 2017 exhibition, featuring marine life common to the waters around Okinawa, runs until August 13. (Photo by Kazuhiro Nogi/AFP Photo)

A Toyota i-Road electric vehicle drives in a underground parking lot in Tokyo April 9, 2015. Tokyoites will get a chance to zip around town on Toyota Motor Corp's three-wheeled electric car-cum-motorbike from Friday, in a trial aimed at crafting a global business model to reduce gridlock and pollution. (Photo by Thomas Peter/Reuters)

Japanese artist Megumi Igarashi, known as Rokudenashiko, holds her artwork after a news conference following a court appearance in Tokyo April 15, 2015. A Japanese artist on trial for obscenity after making figurines and a kayak modeled on her v*gina said on Wednesday that there was nothing wrong with her artwork and her arrest merely showed how far Japan remains behind the west. Words in the artwork read “Centre. 3D scan”. (Photo by Toru Hanai/Reuters)

Tomomi Ota pushes a trolley loaded with her humanoid robot Pepper as she crosses a street in Omotesando shopping district in Tokyo, Japan, 24 March 2016. Telecommunications and mobile phone carrier SoftBank Corp. opened a robot-staffed store where 10 Pepper humanoid robots welcome customers looking to buy a mobile phone. The store will be opened until 30 March 2016. (Photo by Franck Robichon/EPA)

A Japanese Ground Self-Defense Force Type 92 Mine sweeping vehicle fires a rocket behind a Type 74 armoured tank during an annual training session, which is based on a scenario to defend or retake islands in Japanese territory, near Mount Fuji at Higashifuji training field in Gotemba, west of Tokyo, August 18, 2015. (Photo by Yuya Shino/Reuters)

A store staff walks past other staffs dressed up as Stormtrooper and Death Star Gunner (R) from the film “Star Wars” before launching the film's new toys at Loft Variety Store in Shibuya shopping district in Tokyo, September 3, 2015. New “Star Wars” toys and other merchandise were released in stores across Japan just after midnight local time during a global rollout of the popular products. (Photo by Toru Hanai/Reuters)

Kiyomura Co's President Kiyoshi Kimura (C), who runs a chain of sushi restaurants Sushi Zanmai, poses with a 212 kg (467 lbs) bluefin tuna at his sushi restaurant outside Tsukiji fish market in Tokyo, Japan, January 5, 2017. Kimura won the bid for the tuna caught off Oma, Aomori prefecture, northern Japan, with a 74 million yen (633,000 USD) at the fish market's first tuna auction this year. (Photo by Issei Kato/Reuters)