Over the pole, then straight into the city
London to Tokyo is 5,950 miles and needs the longest-range cabins to fly it in one leg: the Gulfstream G650ER, the Global 7500 and the Falcon 8X make Haneda in about twelve hours, routing over Scandinavia and Siberia. A heavy jet such as the Legacy 650 flies it with one stop, usually in the Gulf or at Novosibirsk depending on routing, and lands about two hours later.
Tokyo is nine hours ahead of London in winter, so an evening departure lands the following afternoon. Haneda's business-jet terminal is twenty minutes from Marunouchi and Roppongi, but its slots are rationed and released in advance, and overnight parking is capped, so the aircraft often positions to Narita after dropping you.
Passport and crew details go to the Japanese authorities in advance, so we ask for them early and handle the slot requests at both airports.