The Japanese - who are hosting Group J in 1972 Olympic host Sapporo - haven't played at an Olympics since they were granted a home nation berth in Nagano in 1998.

After a goalless opening period, Yuto Osawa put Japan in front in the second and the match was then to remain tight until late into the final stanza.

Osawa, however, would find the net again with just four minutes remaining before Go Tanaka added some further gloss to the scoreline.

Croatia's cause wasn't helped by only arriving in Sapporo hours before face-off due to poor weather conditions.

“This was a very important game today,” said Japan coach Greg Thomson.

"We knew the situation with Croatia having to stay in Tokyo last night and travel today.

"They didn't quit.” 

All three tournaments will utilise a round robin system, and in the other game in the group at the Tsukisamu Gymnasium, Ukraine saw off Romania 3-0 thanks to goals from Vladyslav Luhovy, Andri Mikhnov and Artem Gnidenko.

"A win is a win," said Ukraine coach Olexander Savytski.

"Some moments we should have been better."

Japan will now play Romania on Saturday (February 13) with Croatia facing Ukraine on the same day.

Elsewhere, Group H began in Budapest with Poland thrashing Estonia 6-2, while hosts Hungary saw off Lithuania 4-0.

The Poles will face Lithuania tomorrow, with Hungary meeting Estonia.

In Group G in Cortina in Italy, Great Britain won a high scoring affair against The Netherlands, 6-5.

Hosts Italy were in dominant form, thrashing Serbia 8-0.

Britain will now meet the Serbians on Saturday, with Italy meeting the Dutch.

All 12 teams involved are two steps away from the Olympics - with the winners of all three round-robins earning a spot in one of three final qualifying groups for Pyeongchang.

The three winners of those events will progress to the Games in South Korea - joining the hosts and already qualified nations Finland, Sweden, Canada, Russia, United States, Czech Republic, Switzerland and Slovakia.