The women's tournament began as an eight-team tournament featuring Canada, the US, the top five from the
1989 European Championships, and one Asian qualifier. The same formula was used for
1992,
1994, and
1997, but changed following the first
Olympic women's ice hockey tournament at the
1998 Nagano Olympics. The top five teams from the Olympic tournament qualified for the
1999 World Championship, followed by the best three from final Olympic qualification rounds. Beginning in 1999, the championship became an annual tournament and the first divisional tournaments below the Top Division were played. Along with the creation of the lower divisions, a system of
promotion and relegation was introduced, allowing for movement between all divisions. After the
2017 tournament, it was announced that tournament would expand to 10 teams for
2019, having been played with 8 teams since the first tournament in
1990, except in
2004,
2007,
2008, and
2009, where 9 teams played. The
2004 edition featured 9 teams when
Japan was promoted from Division II but no team was relegated from the Top Division in
2003, due to the cancellation of the top division tournament in China because of the outbreak of the
SARS disease. Two teams were relegated from the Top Division in
2004, going back to 8 teams for
2005, but due to the success of the 9-team pool in 2004,
IIHF decided to expand again to 9 teams for
2007. IIHF reverted to 8 teams after the
2009 tournament, and play continued in this format until the expansion of 2019.
Championship format Initially, the tournament was an eight-team tournament divided into two groups, which played
round-robin. The top two from each group played off for the gold, and beginning in 1999 the bottom two played off to determine placement and relegation. In
2004,
2007,
2008, and
2009 the tournament was played with nine nations, using three groups of three playing
round-robin. In this format first place from each group continued on to play for gold, second place from each group played for placement and an opportunity to still play for bronze, and the third place teams played off to determine relegation. Beginning in
2011, the tournament changed the format to encourage more equal games. The top four seed nations played in Group A, where the top two teams got a bye to the semifinals, the bottom two go to the quarter-finals to face the top two finishers from Group B. The bottom two from Group B then play each other in a best of three to determine relegation. Beginning in
2019 the tournament was expanded to ten teams, bringing with it a new format. The ten teams are divided into two groups of five and play
round-robin. In this format, the five teams in Group A and the top three teams from Group B move into the Quarterfinals, seeded A1vsB3, A2vsB2, A3vsB1, and A4vsA5. The bottom two from Group B now play only one 9th place game and both get relegated. As of 2021, the four teams that lose their quarterfinal games enter into a knockout tournament to determine 5th place with the winner earning a spot in Group A for the next tournament, though the 2024 tournament will not include these games. From 2026 on, the ten teams will be put into two groups of five, with the top four teams advancing to the knockout stage while the last-placed teams will play out the relegated team. The tournaments will be moved from April to November each year (Lower divisions from 2027 on).
Lower divisions Outside of the Top Division tournament, participating nations play in groups of no more than six teams. , there are six group tiers across three divisions below the Top Division. Introduced in 1999 as a Division I tournament and Division I qualification tournament, the number of lower divisions rapidly expanded as more national teams gained admittance. By 2003 the lower tiers were formalized into tiered groups of six teams each, called Division I, Division II, and Division III, with promotion for the top team in each and relegation for the bottom team. By 2009 it had grown up to Division V, but in 2012 the titles were changed to match the men's tournaments; Division I became IA, Division II became IB, Division III became IIA, Division IV became IIB, and Division V became IIB Qualification. Promotion and relegation remained the same after the title changes. ==Rules and eligibility==