Scotland manager Gordon Strachan has warned his players not to lose their cool in Saturday's 2018 World Cup qualifier at home to old enemies England.
Scotland-England encounters have traditionally been blood-and-thunder affairs, but Strachan says the evolution of the sport means players can no longer afford to go clattering into challenges.
"We were speaking about it the other day, the 'get into them' kind of theory," Strachan told journalists during Friday's pre-game press conference at Glasgow's Hampden Park.
"It's what a lot of people in Scotland are desperate for us to do when I meet them as I go about.
"But the 'into them' theory died with the pass-back rule and the tackle from behind, better pitches.
"So that weapon that we had years ago, where 'get into them' was well and truly used, it is not used as much now.
"You can't do that. You have to think your way through games; interceptions, being brave on the ball.
"I wish we could use the 'get into them' theory, but we can't use that any more."
Scotland are in fourth place in UEFA qualifying Group F ahead of Saturday's game, six points behind group leaders England, who are on course to secure the one and only automatic qualifying berth.
England have not lost a qualifying game since 2009, but goalkeeper Craig Gordon says Scotland's 1-0 win over Slovenia in March means Strachan's side are full of confidence.
"We played really well and created a lot of chances against a really good team," said Gordon, whose side are two points off a possible play-off place.
"We have got to take confidence from that. It was a really good performance. We kept the ball, passed it and created chances. We probably should have scored a few more than we did.
"But it was what we needed at that particular time in the group. It got us back into contention and if we can perform like we did in that match, then we will certainly cause England a few problems."
Celtic striker Leigh Griffiths has been passed fit to face England despite sitting out training on Monday.