Date: Sunday, 8 February Kick-off: 1500 GMTVenue: Murrayfield
Coverage: Screened live on BBC ONE Wales and online plus full commentary on BBC Radio Wales, BBC Radio Cymru and online & score updates on BBC Radio Five Live
Martyn Williams is arguably the finest open-side Wales have ever produced
Martyn Williams says Wales' aim to become a "great" side has justified his choice to come out of Test retirement.
The Blues open-side, 33, stood down in 2007 but was coaxed back into a Wales shirt in January 2008 by Warren Gatland in time for their Grand Slam campaign.
Williams will again be key as Wales begin their Six Nations title defence away to Scotland on Sunday.
"At the moment we're a good side but we're nowhere near a great side and we all want to be part of that," he said.
Wales also won the Grand Slam in 2005 under Mike Ruddock, but slumped the following season to finish second from bottom.
The 2006 campaign yielded just one win - at home over Sunday's opponents Scotland - and a draw with Italy but was overshadowed by the shock departure of coach Ruddock during the tournament.
But Williams says Wales are much better prepared this time to build on the success of the previous season.
"Last time it kind of felt after we won the Grand Slam as if 'right, that's it, we've done it'," said the Pontypridd product.
It's always a nightmare up in Murrayfield, it's really tough
"Whereas this time we've been constantly reminded we've got to kick on, you know we've got to improve, we want to be a great side not just a good side."
Wales have strength in depth in most positions now but the heirs to Williams' number seven shirt have not progressed as swiftly as Gatland may have liked.
Williams announced his international retirement in October 2007 following Wales' disastrous World Cup campaign under then coach Gareth Jenkins.
But the flanker, who has now won 84 Wales caps, was persuaded to come out of international retirement by new coach Gatland in January 2008.
Their run to a second Grand Slam in four years was sparked by a thrilling come-from-behind win in the opening match in England, Wales' first Twickenham triumph since 1988.
"I've had a new lease of life since I came back, it helps as well when you're successful," Williams added.
"It's not often you get a second chance and I've just been real fortunate that I've decided [to carry on playing Test rugby].
Cardiff Blues have used Martyn Williams sparingly this season
"It could have gone the other way mind you; half-time in England I was thinking 'perhaps it was the wrong decision I made!', but it went really well so, fingers crossed, long may it continue."
While Wales and his regional side the Cardiff Blues have stopped short of wrapping Williams in cotton-wool, the veteran's game-time has been carefully managed.
Gatland has gone on record as saying that he believes Williams can still produce the goods for Wales at the 2011 World Cup, and the player himself is hopeful that is a realistic target.
"I haven't played loads, you know every week, and had a few weeks off here and there," Williams admitted.
"Dai's [Young, the Cardiff Blues director of rugby] been really good with me at the club, then I come here [the Wales squad] for a bit of conditioning so fingers-crossed, yeah, I can keep going.
"I feel okay at the moment... we'll get through this campaign first and reassess after that, but I've been managed really well this season.
"It's just a really good environment here as well at the moment, I think you know you can see everyone's enjoying the training; the intensity has gone up another level.
"There's a really good team spirit here and it's just great to be involved and it's something you want to be part of as long as you can."
Scotland coach Frank Hadden raised some eyebrows when he named a starting XV for Sunday's match without a recognised front-line kicker.
Chris Paterson, Scotland's record points scorer, is dropped to the bench, with the full-back's Edinburgh club colleague Phil Godman likely to shoulder the kicking responsibilities from fly-half.
But Williams' concentration is on the challenges he will face up front, with Scotland going for a mobile back-row and also picking Jason White - for much of his career a specialist blind-side - at lock.
"It's always a nightmare up in Murrayfield, it's really tough you know, they always start really well," Williams said.
"Looking at their pack they've got more or less two sevens there in Ally Hogg and John Barclay, so it's going to be a very mobile pack and very difficult at the breakdown."
Despite his veteran status, Williams says he is still getting better with every season and that fact, injury aside, seems certain to earn him a place in next summer's British and Irish Lions squad to South Africa.
"I still feel I learnt playing the Tri-Nations sides in the autumn, I learnt a hell of a lot playing against those teams and analysing those games after," Williams added.
"Once you think you've stopped improving, that's when you fall behind."