Cullen insists hosts can be a real 'handful' for Ireland
It was Japan 2005 and the Lions were about to take a 3-0 shellacking from the All Blacks on a disastrous tour.
Meanwhile, current Leinster head coach Leo Cullen was at the heart of the engine room in Ireland's two-Test sweep of an overwhelmed Cherry Blossoms side in Osaka (44-12) and Chichibunomiya (47-18).
"We were very much under the radar, in terms of that tour," said Cullen, at yesterday's opening of the Leinster Ken Wall Centre of Excellence at Energia Park in Donnybrook.
"It was a great experience, I must say, I enjoyed the time I was there, the two Tests.
"There was an unknown quantity back then. Now, it is almost like the rugby world is much smaller."
The information systems that have saturated the world in the last 10 years have made it impossible to appear as an unknown quantity.
Oh, there is also the small matter of what Japan - then coached by current England supremo Eddie Jones - did to South Africa in the last World Cup in what ranks as the biggest shock in the short history of the competition.
Joe Schmidt will certainly have mapped out a way forward and, probably, through Japan on Saturday.
International Rugby Newsletter
"There is so much more information out there. You know more about the teams," Cullen adds. "Japan have come to the fore, particularly in that 2015 World Cup. A lot of those guys are still around and they feature in Super Rugby.
"The knowledge on them is much greater whereas we were completely blind going into those games in 2015.
"We focused more on ourselves whereas there is the analysis Ireland can do on Japan now from the Pacific Nations tournament before the World Cup."
There was also the 41-8 clobbering they took from the Springboks at the start of the month.
There was more than a pinch of flattery about the outcome.
Rattle "Even that game against South Africa, I watched that game after knowing the result," said Cullen.
"Jeepers, Japan actually gave South Africa a rattle that day. There were a couple of breakaway tries near the end that distorted the scoreline.
"Yeah, they are going to be a handful, Japan, the way they are able to play.
"They have very smart coaches and would have been building for this game for a long time.
"Ireland and Scotland, they will know them well, would have pulled apart their Six Nations games."
The Japanese will stick to what makes them troublesome. Their game is based around movement and staying away from the set-piece foundation, so beloved of traditional nations.
"You can see from the games on the weekend, it was hot and wet," added Cullen.
"Even when it's not raining, it has the look of raining because of the humidity and the way guys are sweating.
"The conditions part is an issue," he said.
The experience of Yokohama is something Ireland can take with them to Shizuoka.