Despite the fact that so many of those who togged out when Ireland were last here in Shizuoka have since fallen into the international wilderness, the summer tour of 2017 can be seen as hugely significant for two reasons.
nly ten of the 23 who beat the Brave Blossoms so comfortably in the same Shizuoka Ecopa Stadium where the pair meet again in the World Cup on Saturday have made the trip this time around - and indeed five have not played for Joe Schmidt again since boarding the plane home - but, for the debut of James Ryan, and re-emergence of Cian Healy, the ripple effects of that summer can still be felt two years on.
With Jack McGrath Ireland first choice loosehead in New Zealand with the Lions at the time, Healy had a prominent role as Ryan made his Test debut in the USA before playing in one of two Tests in Japan, all this despite not having yet played for Leinster.
Two years on and now arguably Ireland's most important player, the ground galloped across so quickly is remarkable.
"It’s incredible what he’s doing and just the shape he's in," said Healy who has had a close-up view for every step of the way.
"He’s young, he’s put himself forward to be where he is and he’s worked incredibly hard at it. He doesn’t have a ceiling to where he can go to, he just keeps getting better and better and I don’t see it stopping.
"Just watching on, it's something to take for any of the other players, to see how he trains and how he works. He works on every side of the game, I've roomed with him before and he's sitting in the corner writing his notes before bed and seeing how much of a professional he is, it's great to see."
Ryan is growing into more of a leader now too. It was noticeable during the summer series that his input was given during key decision-making conversations on field and it's now seen as inevitable that he will captain the squad sooner rather than later.
"He has a bit to say and he's pretty stern about saying it as well which is good," said Healy. "He was fairly quiet at the start and hard to get a bit out of it but you knew there was something in there but he's coming out now as a bit of a comic as well so you're getting to see the full side of James now.
"I don't know if he was just absorbing everything as a young lad.
"That would have been his first run at it and I think everyone wants to absorb those opportunities and take everything in as opposed to getting vocal about it."
Having worn the Ireland number one jersey on that same 2017 tour, Healy has not relinquished it since, indeed the same McGrath who beat him to that Lions tour will be making his PRO14 debut this week for Ulster having had to move north for game-time.
Having benched in 14 of his 20 Test prior, he is now once again undisputed first choice, starting on 19 of the last 25 occasions he's pulled on a green jersey.
Admitting that he'd have a more "reasonable" outlook now should he end up on the bench again come Saturday, Healy is wary of the threat of a side who failed to fire against Russia when afflicted by opening night nerves last week.
"They play such a high-tempo game," he said. "They’ve got a lot of great ball players and finishers so it’s going to be a tough preparation for it. I’d say we’ll be pushed for speed work in training, it’s something we’ve been working on anyway but it’s something we’ll be nailing down to be able to handle that attack of theirs.
"From what I have seen, it's a power game, it's fast and it's putting people under pressure.
"Their fitness is a huge thing which is going to test people. That was probably similar to when we last played them, their fitness was something that massively stood out.
"My review days will be, over the next few days, of the Japanese team, to get more of an insight into what they're doing technically."