Tokyo - Wales skipper Alun Wyn Jones might be a "grumpy" leader, but his warrior-like ethos has made him a lynchpin for a Welsh team that take on South Africa in the Rugby World Cup semi-finals on Sunday.

Jones, 34, is the world's most-capped lock, with 132 caps for Wales, and nine more for the British and Irish Lions.

A one-club player with Welsh region Ospreys, Jones has enjoyed remarkable longevity for a lock forward, traditionally one of the most physically demanding positions on the pitch.

For Wales and the Lions he has formed an axis of power with coach Warren Gatland, who will quit the Welsh after the World Cup but has signed up to lead his third Lions tour, to South Africa in 2021.

The second-rower has won four Six Nations (and three Grand Slams) in his 13-year international career, also skippering the Lions to victory in Australia in 2013 and helping them to a drawn series against New Zealand four years later.

"The thing about Alun Wyn is it's always what's next, he is always motivated, which is why he is such a fantastic player," said Wales defence coach Shaun Edwards.

"Besides his physical prowess and his skills, it's his mental approach which sets him apart."

A Swansea University law graduate, he cuts an imposing figure on the pitch, standing 6ft 5in (1.96m) tall and weighing in at 125kg.

"Alun Wyn's an incredible competitor," said Edwards. "He's unbelievably competitive and he's unbelievably tough.

"He's a very, very brave person. He sets the example for everybody."

'Gets better with age'

Wales' Kiwi-born centre Hadleigh Parkes said Jones would "do anything for the boys".

"As a leader he speaks really well. But he doesn't just speak he leads from the front and you can tell that by the way he puts his body on the line both for country and club is superb," Parkes said.

At 34, Jones might be considered to be coming to the end of his storied career.

Far from it, as last season's Six Nations player of the year more often than not sees out the full 80 minutes of every Test he plays and continues to win plaudits.

"I was lucky enough to be involved with Alun Wyn in the under-21s in 2006 and I could already see he was a pretty special player," said Wales skills coach Neil Jenkins.

"He seems to get better with age. It is difficult to look past Alun Wyn, he's an incredible rugby player, probably up there as one of the best if not the best, you can argue that."

Edwards said the lock continued to develop. "I personally think he's now a better player than he's ever been.

"Long may he continue to be. One of the best players I've ever coached, without a doubt.

"It's only probably when he is not there that you realise how good he is."

Reluctant star

Jones is not one to search out the spotlight and can sometimes come across as being overly reluctant in the eye of the media.

"Mondays are the most interesting days where he's mostly grumpy," admitted Jenkins.

"He's probably a little bit better..."

Jones has committed himself to staying with the Ospreys and Wales, turning down what would have been a deserved end-of-career bumper pay cheque in France or England.

It means he will remain in contention for Wales and the Lions, but Gatland, speaking in June, believes Jones could even kick on through to the 2023 World Cup should he continue to be properly managed.

"It's a possibility if he is on limited games - he is playing the best rugby he has at the moment," he said.

"But two years is a long time in sport and you never know, lots can change."

In Gatland, Jones found a coach with a similarly hard-nosed attitude to the game.

"With regards to Gats, it's funny because the planning for this World Cup has probably been in his head for the last 10 years rather than the last four, two or 18 months," Jones said of the Kiwi.

"He is constantly building, and what we have achieved or have not - whether it is strength in depth, training facilities or whatever - comes to this moment."

Teams:

South Africa

15 Willie le Roux, 14 S'bu Nkosi, 13 Lukhanyo Am, 12 Damian de Allende, 11 Makazole Mapimpi, 10 Handre Pollard, 9 Faf de Klerk, 8 Duane Vermeulen, 7 Pieter-Steph du Toit, 6 Siya Kolisi (captain), 5 Lood de Jager, 4 Eben Etzebeth, 3 Frans Malherbe, 2 Bongi Mbonambi, 1 Tendai Mtawarira

Substitutes: 16 Malcolm Marx, 17 Steven Kitshoff, 18 Vincent Koch, 19 RG Snyman, 20 Franco Mostert, 21 Francois Louw, 22 Herschel Jantjies, 23 Frans Steyn

Wales

15 Leigh Halfpenny, 14 George North, 13 Jonathan Davies, 12 Hadleigh Parkes, 11 Josh Adams, 10 Dan Biggar, 9 Gareth Davies, 8 Ross Moriarty, 7 Justin Tipuric, 6 Aaron Wainwright, 5 Alun Wyn Jones, 4 Jake Ball, 3 Tomas Francis, 2 Ken Owens, 1 Wyn Jones

Substitutes: 16 Elliot Dee, 17 Rhys Carre, 18 Dillon Lewis, 19 Adam Beard, 20 Aaron Shingler, 21 Tomos Williams, 22 Rhys Patchell, 23 Owen Watkin