The 2006 winners went behind to an early goal but were always in control of the pair’s Blue Division contest at the University of Manchester as they cruised to an impressive 17-4 win.
Attackman Zack Greer top-scored with six goals, while fellow attackers Kevin Huntley and Corey Small both weighed in with hat-tricks as Canada led 4-2 after the first quarter and then won the second quarter 2-0 for a welcome four-goal advantage.
Midfielder Mark Steenhuis bagged a brace, while midfielder Dan Dawson, attackman John Grant Junior and midfielder Shawn Williams were also on the scoresheet for the two-time winners.
Attacker Ken Ikegawa top-scored with two goals for Japan, who took a surprise early lead through attacker Wataru Tsugu. Attacker Sekine Mikisuke was also on target, but the Japanese were overwhelmed by their experienced opponents.
And with victory Canada went top of the Blue Division, before the United States replaced them at the top of the table following their evening 21-5 victory Australia.
It took Japan just under two minutes to take the lead as they came out of the blocks firing on full cylinders and it was not until the eighth minute that Canada levelled matters when Steenhuis scored.
Greer edged Canada ahead in the 12th minute with a well-worked goal, before Ikegawa squared the match for Japan.
But Canada then raised their game and then scored 13 goals without reply as they made the perfect start to their campaign.
Grant Junior netted in the 16th minute, while the impressive Greer scored twice in four minutes to make it 5-2.
Huntley was on target in the 24th minute, but Japan held firm and battled hard until half-time to keep themselves in the contest.
However, Canada raised their game after the break and emerged with a much more aggressive approach as they powered ahead.
Greer, Huntley and two goals from Small came in the space of nine minutes, before Huntley and Greer eased the Canadians into a 15-2 advantage.
Ikegawa scored his second of the match with seven minutes remaining and Sekine scored soon after, but Canada had the final say and scored twice more through Steenhuis – and that man Greer!
A delighted Greer reflected afterwards: “It was a great start for us. We all played well from the goals to the defence, all the way through to the midis to the attack.
“Everyone worked hard and we ironed out some kinks again and we’re looking forward to playing the United States, it’s a big match for both countries.”