With leaders Australia not in action until April 1, victory in Saitama will move Japan a point ahead of the Socceroos at the top of Group 1 and give coach Takeshi Okada some much-needed breathing space.
"While all the games are important, this is the one we have to go for," Okada told Japanese media.
"We'll take risks where we have to. I'm only thinking about winning the match, nothing else.
"Bahrain are a tough match-up for any team, not just us," added Okada, whose side have won two and drawn two of their matches in the fourth and final round.
"Their style is to take away your strengths and make the game difficult for you."
Surprise package North Korea can also move ahead of rivals South Korea in Group 2 with a win against the struggling United Arab Emirates, whose campaign looks sure to be over if defeated.
SAUDI PRESSURE
North Korea are closing in on their first World Cup since 1966 and with South Korea's campaign rapidly gaining momentum, the prospect of both Koreas playing in the finals for the first time looks increasingly likely.
Regional heavyweights Saudi Arabia, however, are at risk of missing out on the finals for the first time in 20 years and new coach Jose Peseiro has taken the bold move of dropping the country's most decorated player to underline his tough approach.
Former Asian player of the year Yasser Al Qahtani is suspended for Saturday's visit to Iran but his recent antics have prompted the no-nonsense Portuguese to dispense with the prolific marksman for the April 1 match with UAE.
"He (Al Qahtani) missed training and didn't reply to repeated phone calls," Saudi team manager Fahad Musaybih said in breaking the news to local media.
Peseiro is confident he can steer the Saudis, who are fourth in the group, to South Africa and recently told Reuters: "My players have the ability, the quality and technical capability to get to the World Cup, I have no doubt about this."
Uzbekistan host Qatar in Saturday's other match in a must-win game of the home side, who have just one point from four matches, despite having dominated the previous qualifying round.
Coach Mirdjalal Kasimov has introduced three new players in a last-ditch attempt to secure third place and a playoff berth for a second-successive campaign. Defeat is likely to bury their hopes of reaching their first World Cup finals.
The top two teams in each group qualify for South Africa 2010. The winner of a playoff between the two third-placed teams take on Oceania champions New Zealand for the final place in the 32-team tournament.
