Japan was more focused on Friday but Switzerland always looked closer to clicking through a scoreless first period.
Linemates Lara Stalder and Alina Muller scored and set up each other’s goals in the second to assert Switzerland command, and Lena Marie Lutz added an empty-netter with 2:05 remaining in a third in which Japan was the better team.
Goalkeeper Miyuu Masuhara was excellent in stopping 17 of 20 shots but was pulled again at 3-0 down and Akane Shiga scored after missing a point-blank chance in the first.
Czechia’s first worlds match under new coach Carla MacLeod, a two-time Olympic gold medalist player for Canada, was one-sided, played almost entirely at Hungary’s end.
Klara Hymlarova posted the first goal after 62 seconds, followed by defender Daniela Pesjova just over a minute later.
Defender Tereza Radova and 16-year-old forward Adela Sapovalivova made it 4-0 before Hungary scored just before the end of the second period through Alexandra Huszak. Hungary was kept to seven shots.
The third period featured scores by Natalie Mlynkova, Sapovalivova’s second, and Agata Sarnovska.
Hungary goalie Aniko Nemeth did well in facing 45 shots to make 38 saves.