Shane Williams will win his 50th Wales cap when he plays Japan

Shane Williams hopes to celebrate his 50th cap on Thursday against Japan by joining fellow wing Ieuan Evans in Wales' all-time try-scoring list.

Evans scored 33 tries for Wales in a 79-Test career and Williams is just one behind going into the match in Cardiff.

With seven tries in three previous matches against Japan, the odds are good Williams could even pass Evans.

"It would be great if I could do it. I grew up watching Ieuan and I remember all his tries," Williams said.

"He just seemed to score for fun so to be up there with him is a privilege.

"The likes of Ieuan and Gerald Davies were players I aspired to, so when people are talking about you scoring more tries than Ieuan Evans it is great.

This is a game where we need to prove the doubters wrong Wales wing Shane Williams

"If we do play as we have done against Japan in the past, especially the last time when we scored 98 points, then I would like to think I would be on the scorebook!"

If Williams overhauls Evans' tally, only fellow current Wales team-mate Gareth Thomas, who misses the Japan match through injury, will be ahead of the diminutive wing - having scored 39 for tries for Wales.

Having lost to Australia last Saturday in a clash between the two Pool B favourites, the main job in hand is to make sure Wales take second in the group to qualify for the quarter-finals.

That means a handsome win against Japan in the Millennium Stadium and then seeing off Fiji in the last Pool match on 29 September in Nantes

Williams, 30, is the man Wales arguably look to more than any other as the catalyst for their attacking game, as the Osprey showed with a try against the Wallabies in that 32-20 loss.

"It is good that when I get involved it seems to get the lads going," Williams added.

"It is very difficult to get involved in a game when you are on the wing and the team isn't playing well. You are the furthest person away from the ball.

606: DEBATE Share your Wales v Japan predictions and reactions with Scrum V on BBC Radio Wales Gareth Lewis

"But I was determined in the second half against Australia to get involved more and be more gutsy and take players on.

"I needed a big performance. I want a big World Cup from myself. I was happy with my performance in the second half against Australia but I want to do that for 80 minutes."

With South Africa almost certainly lying in wait for the Pool B runners-up, Williams says that Wales must play themselves into good form and prove they will be a force to be reckoned with.

"This is a game where we need to prove the doubters wrong, we need to play as we have been in the second half of matches right from the start," he said.

"We want to start the game well, we want the set piece to work well and we want to play an open expansive game."

Another landmark will be reached by Colin Charvis, whose 92nd cap will match Gareth Llewellyn's total as the most capped forward in Wales history.