The Japan national rugby team found out the hard way this week that if there is one thing that upsets a former All Black more than anything it is playing for your country without any passion.

The Brave Blossoms may have opened their Asia Rugby Championship campaign with a 47-29 win over South Korea, but it was a performance that angered head coach Jamie Joseph far more than it pleased him.

Joseph, who won 20 caps for New Zealand and nine for Japan, responded to the performance by making eight changes for Saturday's rematch at Prince Chichibu Memorial Rugby Ground.

"It was a test match Japan won but we didn't perform well," he said Friday after his team's captain's run.

"Last week we gave some young guys a crack and they didn't take it. Some have lost their job and some get another chance because you can't drop everyone."

The six changes up front have resulted in a more physical pack, while the inclusion of Akihito Yamada on the wing gives the team a world-class finisher.

But it is on the defensive side of things that Joseph really wants to see an improvement

"Some of the players weren't willing to get back and make tackles and that's nonnegotiable," he said. "South Korea were more passionate and more aggressive and I expect the same tomorrow plus 30 percent based on the confidence they have gained from that game. Tomorrow will be a tough game."

Captain Yutaka Nagare was one of those singled out for his defensive shortcomings and the scrumhalf admitted tackling would be his main focus on Saturday.

"The team worked really hard on their one-on-one tackling in training this week," he said.

While Joseph was ringing the changes, his South Korean counterpart John Walters has largely kept faith with the same side, making just two changes in the backs.

"We were happy with parts of the performance but a loss is still a loss," he said Friday. "The boys showed good mental toughness and after taking a while to get used to the tempo of the game did well."

However, as South Korea captain Kim Jeong-min pointed out, the rematch is set to be far tougher given the stern words the Brave Blossoms received from Joseph during the week.

"We will need to be even stronger mentally and really focus on our defense," the 34-year-old openside flanker said.

Two players who avoided Joseph's direct wrath were flyhalves Jumpei Ogura and Takuya Yamasawa.

"I thought he played well and has been rewarded with another chance," Joseph said of Ogura, who will be looking to put the likes of Ryohei Yamanaka and Yamada into plenty of space.

Yamasawa, meanwhile, watched last week's game in Incheon from the stands and is set to win his first cap off the bench.

Picked for Japan A while still at high school, the 22-year-old flyhalf became the first student to play Top League rugby last season when the University of Tsukuba allowed him to play for Panasonic Wild Knights rather than suit up for the collegiate championship.

"He has got the skill set we are after but is very young and still has a long way to go," Joseph said. "He will get on in the second half and hopefully we will be in a better position than we were last week."