Scotland must take inspiration from Japan and try to become "the best 'small' team in the world", says England head coach Eddie Jones.
Jones also suggested Gregor Townsend's side "got their physical conditioning wrong" as they failed to make it out of their pool at the World Cup.
Hosts Japan eliminated Scotland on their way to the last eight, where they lost to eventual winners South Africa.
"Gregor's got them back playing how a Scotland side should play," said Jones.
"[A lack of size] makes it difficult but you can have one-off success like Japan have had.
"You've got to pool all your resources into being the best 'small' team in the world.
"That means you look at everything you do, at how you can win ball quickly - particularly from set-piece.
"You look at how you can win the ball quickly from the breakdown and you need a consistent programme for four years to be at your best to do that.
"You have to play quick, you have to have a varied attack and it takes a lot of cohesion to play that way."
Jones, 59, coached Japan for three years including leading them at the 2015 World Cup, where they lost to Scotland as they became the first nation to record three pool-stage wins and not reach the last eight.
He then took charge of England, winning the Six Nations in 2016 and 2017 before finishing as runners-up to South Africa in Japan at the beginning of November.
His side produced a colossal performance to upset holders New Zealand in the semi-finals but lost a week later against the powerful Springboks.
Too much running before the World Cup?
Scotland's tournament was a huge disappointment, failing to reach the last eight for just the second time following defeats by Ireland and Japan.
Jones' observations about the side's conditioning are at odds with Townsend's claim his squad would be "the fittest at the World Cup".
"We have great respect for the Scottish team and the way they play," said Jones. "Scotland is the smaller country, with smaller resources that has to battle harder.
"I see a very loose team that wants to break the game up, that relies a lot on the number 10 [Finn Russell] for inspiration.
"Where they came unstuck at the World Cup is possibly they got their physical conditioning wrong.
"The first pre-World Cup game [a 32-3 warm-up loss in France] gives you a pretty good indication of where a team is going to be. They looked like they had over-ran but that's a judgement from a long way away."
While Jones thinks the Six Nations is "probably about the right length", he would like to see Japan get a taste of the action after their World Cup heroics.
"I think 10 internationals a year in the northern hemisphere is about right," Jones explained. "To increase the Six Nations would mean taking away from somewhere else.
"I'd bring Japan in for bye-weeks, so they'd play two games over the next three of four years to prove they are strong enough to compete consistently."