Japan captain Makoto Hasebe has declared himself "ready to go" for his team's World Cup Group C opener against Ivory Coast in Recife at the weekend, shrugging off worries over a knee injury.

"There is no problem (with the knee) and I have been taking part in full training," the Eintracht Frankfurt defensive midfielder said after Wednesday's workout at Japan's World Cup base camp in Itu, near Sao Paulo.

"Obviously it is the coach that decides but I am ready to go," the 30-year-old said about the chance of his making the first team for the match which kicks off at 11pm local time on Saturday (0200GMT Sunday), according to Kyodo News.

Japan coach Alberto Zaccheroni has shown great faith in Hasebe since taking over the Blue Samurai after the 2010 World Cup, depending on him to help fulfil the goal of at least a quarter-final spot in a team studded with talent, including Manchester United's Shinji Kagawa and AC Milan midfielder Keisuke Honda.

Hasebe suffered a torn lateral meniscus in his right knee playing for his former club Nuremberg in a January friendly.

He underwent surgery twice on the knee but played the full 90 minutes in Nuremberg's final game of the season and played the second half in Japan's 1-0 friendly win over Cyprus at home on May 27.

But he sat out Japan's last two warm-up matches in which they beat Costa Rica and Zambia at their training camp in Florida.

Hasebe and Stuttgart defender Gotoku Sakai had been the only real injury concerns for Zaccheroni but the Italian tactician now has a fully fit squad.

Japan have shown attacking flair, scoring seven goals in the Florida friendlies, but their leaky defence yielded four.

Hasebe said Ivory Coast have similar problems.

"Ivory Coast are strong in attack but on the other hand they are a bit flimsy in defence," he said. "We are both attacking teams and I think it will be the team with the highest levels of concentration that will come out on top."

Japan will also face Greece and Colombia in Group C.