Wales fought off a spirited Japan display to secure a 28-21 Nations Championship victory in Cardiff.
Josh Adams added a brace of tries to scores from Archie Griffin and Louis Rees-Zammit as Wales claimed a bonus-point win -- their second from four games in the competition.
Sam Costelow kicked three conversions and replacement Dan Edwards one, with Wales relieved to hear the final whistle.
Ben Gunter, Warner Dearns and Kenta Fukuda replied with Japan tries, as Naoto Saito (2) and Shinya Komura added six points with the boot.
Wales had to hold on for only the fourth win in Steve Tandy's 13 games -- two of which have come against Japan.
But the fact New Zealand and Australia are next up for Wales will be of concern to home fans, many of whom chose to stay away with the domestic game in turmoil.
Rows and rows of seats were empty at Principality Stadium, with a crowd of 52,425 more than 20,000 below capacity.
This was the fourth meeting between the two sides in 16 months, with Wales needing a last-gasp penalty to win in Cardiff 12 months ago by a single point.
Wales had a record 12 players from English clubs in their 23, with nine -- including six forwards -- in the first XV, and many of them were shining in the Gallagher Prem.
Bristol's Rees-Zammit had the crowd on their feet with a 35-metre break in the first minute and Wales built from good field position as prop Griffin crashed over for his first Test try and Costelow converted.
Rees-Zammit was having plenty of touches in an open contest that Japan coach Eddie Jones had predicted and threatened at every opportunity.
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But Japan levelled from turnover ball as Welsh numbers were exposed and Gunter eased past Adams.
The charging Aaron Wainwright was brought down by a last-ditch tackle as Wales sought to bring more structure to their game and go through the phases.
Wales regained the lead after 27 minutes when Eddie James sent Jac Morgan clear down the left touchline.
Morgan spotted Rees-Zammit who, having switched wings, popped up a pass for Adams to finish and Costelow to convert.
Japan responded instantly as lock forward Dearns went over from close range and Saito added the extras again.
Wales went to the break 21-14 ahead as Rees-Zammit took Blair Murray's pass on the touchline and stepped off his right foot to shrug off three defenders, although it needed a goal-line intervention from Nicky Smith to deny Japan right on half-time.
Wales were starting to dominate in the scrum and that allowed a period of pressure, which was wasted by clumsy handling.
Japan were also helped by a misfiring Wales line-out that coughed up possession on their own throw six times.
Relief was palpable 12 minutes from time when Murray picked up a loose ball and scampered down the touchline.
Murray moved inside to find the supporting Tomos Williams and the scrum-half freed Adams for his 25th Wales try and precious breathing space.
But Fukuda set up an anxious finish after breaking through five minutes from time.