Nine-hundred invited spectators on Friday watched Japan get its preparations for the London Olympics under way without the driving force behind its astonishing victory at last summer's Women's World Cup.

Star midfielder and team captain Homare Sawa is sitting out the four-day training camp in Wakayama Prefecture, the team's first of the Olympic year, with a pulled right calf muscle that will need three weeks to heal.

But coach Norio Sasaki said he was optimistic the newly crowned FIFA Women's Player of the Year would win a race against the clock to be fit for an important pre-Olympic invitational tournament in Portugal later this month.

"Sawa and (defender Asuna) Tanaka are not in good shape so we didn't want to call them up and make them do the impossible," Sasaki told reporters. "But it has been a good first day and I have seen positives."