Japan booked its place at the 2015 Rugby World Cup with a 49-8 win over Hong Kong on Sunday in the final sporting event at National Stadium before it is demolished and rebuilt to stage the 2020 Olympics.

Japan claimed its eight-straight World Cup berth and seventh-straight Asian 5 Nations title with the win, which saw the Brave Blossoms establish a solid halftime lead before taking their foot off the gas early in the second period and eventually going on to run up the score.

A crowd of 16,371 turned out to say farewell to National Stadium before it is torn down to make way for a new venue to host the 2019 Rugby World Cup and 2020 Games, and Japan coach Eddie Jones was proud to have played a part in the iconic stadium's swan song.

"It was a tough old game," he said. "We have achieved our first goal to qualify for the World Cup, which is fantastic. The next target is to reach the quarterfinals of the World Cup, so from now on everything we do is about making sure we are in a position to make the quarterfinals.

"You look at the background and see the flames there that were lit 50 years ago, and to play the last game at Kokuritsu was a special occasion for us."

Two tries from Yoshikaze Fujita and one each from Harumichi Tatekawa and Justin Ives gave Japan a 27-3 halftime lead, but Hong Kong held the home team scoreless for 27 minutes of the second half and scored a try itself through Thomas McQueen.

Japan redoubled its efforts to add a comfortable sheen to the final scoreline, however, with Shinya Makabe crossing the line before Fujita completed his hat trick and Takeshi Kizu and Keisuke Uchida got in on the action.

"Winning was the important thing," said Japan captain Michael Leitch, who took over as skipper for this year's A5N tournament, in which the Brave Blossoms maintained their record of never having lost a single match in the seven years of the competition's existence.

"Hong Kong have improved since the last time we played them, and they pressured us at the breakdown and stopped us from playing our game. We made some individual mistakes and we have to fix them moving forward."

Hong Kong, which has never appeared at the World Cup, finished as A5N runnerup and now faces Uruguay in the first round of the qualifying repechage for England 2015.

"We always knew it was going to be a tall order," said Hong Kong manager Dai Rees, who will now lose one of his coaches, Leigh Jones, to Japan's coaching staff. "We could dream at 8-0 and 13-3 that we were still in the game, but we made too many mistakes around halftime which gave confidence to Japan.

"It was the first time ever that the championship has gone down to the last game, and it was a great occasion being the last game in the stadium. We wish Japan all the best in the World Cup finals taking one of our backroom staff with you."