Japan will "fight like samurai" in their World Cup last-16 clash with Croatia on December 5 (10pm Cambodian time) as they battle to reach the quarter-finals for the first time, defender Yuto Nagatomo said.

Japan reached the knockout round after stunning Germany and Spain to top Group E but they are not satisfied with what they have achieved so far in Qatar.

Veteran Nagatomo is appearing at his fourth World Cup and urged his team-mates to "show the samurai spirit to the world" against Croatia.

"Before battle, the samurai would polish their weapons and refine their technique, but if they were scared in battle, all that would count for nothing," the former Inter Milan left-back said on Sunday.

"It's the same as football. Of course tactics and technique are important, but if we're scared, it doesn't matter how much we've trained over the past four years because our technique will be no use.

"The most important thing is to have courage," the 36-year-old added.

Japan have reached the last 16 at three previous World Cups but they have yet to make it as far as the quarter-finals.

They were eliminated in the first knockout round four years ago in Russia when they threw away a two-goal lead to lose 3-2 to Belgium with the last kick of the game.

Nagatomo said the defeat had been on his mind for the past four years and he is ready to wipe away the memory against Croatia.

"The past four years have been tough for me but I think we have all overcome that and improved as players," he said.

"I have been playing for Japan for almost 15 years and as far as I can see, this is the strongest team we've ever had at the World Cup."

Four years of sacrifice

Japan had to come from behind to beat both Germany and Spain, and were forced to defend for long periods against opponents who dominated possession.

Coach Hajime Moriyasu wants his players to have more of the ball against Croatia but urged them to show "resilience" whatever the situation.

"The players showed their ability against Germany and Spain, they were united as a team and dug in and fought until the end," he said.

"They have proved that when they play like that, it brings results.

"Of course it's important to think about our opponents but first of all I want our players to show what they can do."

Japan will be playing in the knockout phase of the World Cup in successive tournaments for the first time.

Captain Maya Yoshida said the players have had to "sacrifice a lot over the past four years" and urged them to make it worth the effort.

"For Japanese football to move up a level, we have to become the kind of team that can consistently get through to the knockout rounds at the World Cup," he said.

"We can't be satisfied with what we've achieved – we have to write a new chapter in our history."