The US Women's National team may be the top ranked team in the world, boasting some of the best talent the game has to offer. As they move toward the 2012 Olympic Games, a clear obstacle has emerged in the quest to repeat as Olympic champions: Japan.

The same team that kept the Americans from capping their dream run in the 2011 World Cup with a championship will be the chief threats to keep the gold medal from the Americans. Even though last year's World Cup loss in penalty kicks could be chalked up to the unluckiness of penalties, the United States has yet to find a way to beat their rivals to the East in their previous last two meetings.

The United States faces two tough rivals in the upcoming Volvo Winners Cup in Sweden, including a Sweden side currently ranked third in the World. Most of the focus in the upcoming matches will be how Pia Sundhage's side deals with a Japanese team that has become their most difficult opponent, the only team they haven't beaten this year despite facing them twice.

"If you count Japan's chances, there aren't that many, but they create big chances and at the end of the day they win a lot of games," Sundhage said of Japan. "It's because of the way they play. They keep possession and they're very patient in the attack.

"They're very comfortable with the ball and they work together," Sundhage said. "It's not about them having one player who is fantastic and is the star. They play as a team, they knock around the ball and they do it together. Also, the way they defend, they're committed and everyone is on the same page."

The US women face Japan on Monday, but must first contend with a strong Sweden side that will surely be looking to improve on the 4-0 drubbing the Americans handed the Swedes on March 7 in the Algarve Cup in Portugal. Saturday's Volvo Winners Cup opener against the host should be a good test ahead of the big Japan match, and it should also help the Americans in their preparation for the Olympic opener against France.

Though it doesn't boast the history of say the USA-Brazil rivalry, or even the USA-Germany, the Japanese have become a world power in recent years. Their stylish and patient style has served as the perfect foil to the US team's fast and athletic approach, which normally wears out opponents. The Japanese defeated the United States 1-0 on March 5 in Portugal before the teams tied 2-2 in Japan on April 1.

"Japan has always been a well-respected team, and had been in the top five for so many years, but until the last year I don't think anybody would have said they're the team to beat," said US midfielder Heather O'Reilly. "Their confidence right now, and being able to score huge goals in tight games, has really been the difference right now and I think it's done a lot for their confidence."

The upcoming friendlies are not just about beating Japan though. The friendlies are the two best tune-up matches before the Olympics, and the two best opportunities for Sundhage to see what systems and lineups look best heading to London.

The US will deploy both a 4-4-2 and 4-2-3-1, with the 4-4-2 being the preferred system as Sundhage looks to keep Alex Morgan and Abby Wambach on the field together. This doesn't mean we will not see the 4-2-3-1 in London. In fact, there's a good chance Sundhage will trot out the one-forward system in one of the two matches in Sweden.

"Our job is to make sure we're comfortable playing two systems," Sundhage said. "Depending on who we're playing, and depending on the score. There's a lot of games in the Olympics in a short amount of time. Resting players and the best position for the players available will let us know what we can use, and that's something we have to figure out before we go to London."

Another answer Sundhage will be looking to find is which midfield combination will be the best option heading into the Olympics, and particularly the difficult opening match against France on July 25. Carli Loyd and Shannon Boxx are the veteran tandem in the middle, but Sundhage's desire to inject more passing flair into her lineup means someone like Lauren Cheney and Megan Rapinoe could be given a chance to prove their worth as starters.

"If you look at Megan Rapinoe, Tobin Heath and Lauren Cheney, we have some players who can bring that special attacking element in midfield, and it is something we want to see how we can incorporate that," Sundhage said. "The good thing is we have enough options to try not only different combinations but different systems, which will only help us at the Olympics."

More importantly, something else the Americans will want to figure out before the Olympics is whether they can beat the Japanese. There are several teams capable of winning the gold medal this summer, but no team has the USA's number in the past two years like Japan.

For Sundhage, beating the Japanese isn't as important as trying to learn from their rival. Her admiration for the skillful style of play employed by the Asian powerhouse is clear it's a style she wouldn't mind her own team to implement into their own game.

"We need to be more patient in the attack, we need to be able to find the third runner, or finding the second space," Sundhage said. "It starts with them keeping the ball. I think that's good for women's soccer in general. I think it's very attractive and it's fun to play that kind of soccer as well."