Wales skipper Colin Charvis ran in a record-equalling four tries as Japan were out-classed at the Millennium Stadium on.
A confident Welsh side jogged in 14 converted tries against a Japanese team who had already conceded 100 points to Scotland on this tour and narrowly avoided doing the same in Cardiff. The home side had racked up five converted tries by the 20-minute mark and showed little sympathy for their visitors in front of 56,380 fans at the Stadium - a bigger crowd than the one who watched the South African Test three weeks ago.
The Japanese defence held firm for exactly three minutes before backrower Charvis scored his 14th try in the red jersey after the Welsh rolling maul encountered little resistance on their march to the try-line.
From the kick-off, fullback Rhys Williams found a hole in the visitors' defence and it was 14-0 after barely six minutes. A break from winger Shane Williams set up Charvis for his second try and the result of the match was decided before some fans had found their seats.
The next player over was hooker Mefin Davies as Charvis was brought down inches from the line, before another Williams break set up centre Tom Shanklin for his sixth try of the autumn Test series.
Shanklin bagged his seventh before the half-hour mark and Gavin Henson's sixth straight conversion gave his side a 42-0 lead. The dynamic Charvis completed his inevitable hat-trick a minute later and fans were starting to wonder if the Japanese side had actually turned up.
Things got even more ridiculous when prop Gethin Jenkins romped over the tryline from 20 metres out to take Wales past the 50-point mark, and the 56-0 scoreline at halftime was great news for the hundreds of Welsh fans who had backed their side at odds of 7-2 to score a century of points.
Whatever Japan coach Mitsutake Hagimoto said at the break had little effect on his side and Charvis was soon over for his fourth try - equalling the Wales record for one match and joining the likes of legendary Welsh wingers Ken Jones and JJ Williams on 17 Test tries.
Japan stemmed the flow for 10 minutes, but Wales' 10th try was always going to come and it went to scrum-half Gareth Cooper, who flicked a lazy dummy to the defenders and jogged over beneath the posts. Henson's 10th conversion gave his side a 70-0 lead as coach Mike Ruddock began clearing his bench.
From the next play, elusive winger Shane Williams cut inside to score his first try of the autumn series and 20th overall to join Gerald Davies and Gareth Edwards as the equal third-highest try-scorer in Welsh history.
The century mark edged closer when Shanklin completed his hat-trick and Henson became the first Welsh player to kick 12 conversions in a Test match.
The Cherry Blossoms refused to give up, though, and seemed determined to prevent the home side from reaching three figures. They attacked the Welsh line five consecutive times before the inevitable turnover and Shane Williams was over for his second try after a brilliant handling move that involved five players and 90 metres of Millennium Stadium turf.
Rhys Williams joined in on the act when he found an inch of space on the right-hand touchline and he sprinted 80 metres to score in the corner, and the tight angle was no problem for the brilliant Henson, who slotted his 14th straight goal.
Just when it seemed a century was inevitable, a knock-on and a forward pass stopped Wales in their tracks and referee Henning put Japan out of their misery with the final whistle.
Wales (56) 98
Tries: Charvis (4), R Williams (2), Davies, Shanklin (3), Jenkins, Cooper, S Williams (2)
Cons: Henson (14)
Japan (0) 0
Wales: R Williams (Blues); H Luscombe (Dragons), G Henson (Ospreys), T Shanklin (Blues), S Williams (Ospreys); C Sweeney (Dragons), G Cooper (Dragons); Duncan Jones (Ospreys), M Davies (Neath RFC), G Jenkins (Blues), M Owen (Dragons), J Thomas (Ospreys), Dafydd Jones (Scarlets), C Charvis (Newcastle, capt), R Jones (Ospreys)
Replacements: S Jones (Dragons), A Jones (Ospreys), A Popham (Leeds), M Williams (Blues), M Phillips (Scarlets), M Watkins (Scarlets), K Morgan (Dragons)
Japan: R Miki (World Fighting Bull); K Kubota (NEC Green Rockets), M Mukoyama (NEC Green Rockets), Y Motoki (Kobelco Steelers), H Daimon (Kobelco Steelers); H Yoshida (Kubota Spears), W Ikeda (Sanyo Wild Knights); Masahito Yamamoto (Toyota Motor Verbitz), T Yamaoka (Suntory Sungoliath), R Yamamura (Yamaha Motors), H Kiso (Yamaha Motors), T Kumagae (NEC Green Rockets), F Mau (World Fighting Bull), N Okubo (Japan RFU), T Miuchi (capt, NEC Green Rockets)
Replacements: Mitsuga Yamamoto (Sanyo Wild Knights), Y Hisadomi (NEC Green Rockets), T Yamaguchi (Kubota Spears), H Ono (Toshiba Brave Lupus), K Tanaka (Suntory Sungoliath), S Shimomura (Sanyo Wild Knights), K Sawaki. (Suntory Sungoliath).
Referee: Tappe Henning (South Africa)