Japan duly beat South Korea in their Asia Rugby Championship opener Saturday but it was hardly an impressive performance from Jamie Joseph's side.

The Brave Blossoms may have scored seven tries but they conceded five in a 47-29 victory at Incheon Namdong Asiad Rugby Field that left Joseph less than impressed.

"We were out-passioned and that's the disappointing thing for me," said the former New Zealand and Japan international.

"We had 11 new caps and I wanted them to leave everything on the field. I thought there would be more passion. And some of the more experienced players didn't want to do the hard work early on."

As Joseph pointed out, the quick start that saw the Brave Blossoms score two tries through Ryoto Nakamura and Kazuhiko Usami before the fans had a chance to get seated after the national anthems was, in part, the reason for the poor performance.

"Those two tries in five minutes put our guys to sleep and we nearly paid the price," he said.

That complacency allowed the hosts to bounce back with two tries of their own in quick succession as Japan's defensive frailties were exposed at the set piece with Han Kun Kyu and Kim Jeep giving the locals something to cheer as the South Korean forwards outmuscled the visitors.

With Japan captain Yutaka Nagare trying to urge his team to show a bit more commitment to the national jersey, the Brave Blossoms temporarily awoke from their slumber with Nakamura and Usami making it a brace apiece and Ryuji Noguchi crossing on his international debut as the teams turned around with Japan leading 35-12.

It was the South Koreans, however, who dominated the second stanza.

Lee Yong Seung touched down 20 second after the restart and Shin Ki Cheol followed him onto the score sheet soon after as the hosts showed new found mental fortitude.

"We have a bit more experience and have understood what it is to stay in the moment," explained South Korea assistant coach Deon Muir.

A second five-pointer from Noguchi and a close-range effort from Shintaro Ishihara ensured there was no way back for the South Koreans.

But it was the men in white who had the final say with the impressive Chang Yong Heung finishing off a 90-meter effort that began with a good angled run from Mun Jeong Ho.

"It's not how you start but how you finish, though we will need to improve next week," said South Korea coach John Walters, whose side travel to Tokyo for next week's return game.

Joseph, meanwhile, said his side had plenty to work on in the next seven days.

"We have got to make our tackles as that would have denied them many of their opportunities," he said. "But hats off to South Korea, they played with a lot more spirit than we did."

==Kyodo