J2 League
Sejarah > Timeline

| Year | Important Events | # J2 Clubs | Prom>  Slots | Rel>  Slots |
| --- | --- | --- | --- | --- |
| 1999 |  The J.League adopts two divisions, as nine clubs from the former Japan Football League join Division 2, along with the relegated Consadole Sapporo: Montedio Yamagata, Vegalta Sendai, Omiya Ardija, Kawasaki Frontale, Ventforet Kofu, Sagan Tosu, FC Tokyo, Albirex Niigata, and Oita Trinita  The Japan Football League is also restructured, as it becomes the third-tier Japan Football League (JFL). Note: To distinguish between the former and the current JFL, the new JFL is pronounced Nihon Football League in Japanese. | 10 | 2 | 0 |
| 2000 |  Mito HollyHock is promoted from Japan Football League | 11 | 2 | 0 |
| 2001 |  Yokohama FC is promoted from Japan Football League | 12 | 2 | 0 |
| 2002 |  Extra time is abolished in Division 2 and traditional 3-1-0 points system is adopted | 12 | 2 | 0 |
| 2003 |  | 12 | 2 | 0 |
| 2004 |  Inception of the two-legged Promotion/relegation Series as the top flight expands to 18 clubs in the following season | 12 | 2.5 | 0 |
| 2005 |  J.League Division 1 expands to 18 clubs (No relegated clubs from the 2004 J1 season)  Tokushima Vortis and Thespa Kusatsu are promoted from Japan Football League | 12 | 2.5 | 0 |
| 2006 |  Ehime FC is promoted from Japan Football League  Away goals rule is adopted in Promotion/relegation Series  The league forms J.League expansion committee and reintroduces J.League Associate Membership | 13 | 2.5 | 0 |
| 2007 |  | 13 | 2.5 | 0 |
| 2008 |  Two clubs are promoted from Japan Football League: Roasso Kumamoto and FC Gifu  Division 2 adopts the triple-round-robin format from quadruple-round-robin | 15 | 2.5 | 0 |
| 2009 |  Three clubs are promoted from Japan Football League: Tochigi SC, Kataller Toyama and Fagiano Okayama  Promotion/relegation Series is eliminated and the third-place club now receives automatic promotion to J1 | 18 | 3 | 0 |
| 2010 |  One club is promoted from Japan Football League: Giravanz Kitakyushu  Division 2 adopts the double-round-robin format from triple-round-robin | 19 | 3 | 0 |
| 2011 |  One club is promoted from Japan Football League: Gainare Tottori | 20 | 3 | 0 |
| 2012 |  Matsumoto Yamaga and Machida Zelvia are promoted from Japan Football League  The playoff system for the third promotion spot is introduced  Conditional relegation to Japan Football League is introduced. Machida Zelvia became the first club to be relegated from Division 2. | 22 | 3 | 1 |
| 2013 |  One club is promoted from Japan Football League: V-Varen Nagasaki  Gainare Tottori became the first club to be relegated to the new J3 League after losing the promotion/relegation Series to Kamatamare Sanuki, the last team to get promoted from the Japan Football League. | 22 | 3 | 0.5 |
| 2014 |  Kataller Toyama has been relegated to J3, and Kamatamare Sanuki played and won the first promotion/relegation Series with the J3 runners-up. Zweigen Kanazawa becomes the first team to be promoted from J3. | 22 | 3 | 1.5 |
| 2015 |  Tochigi SC has been relegated to the J3, and Oita Trinita played and lost their first promotion/relegation Series with the J3 runners-up. Renofa Yamaguchi and runners-up Machida Zelvia are promoted from J3. | 22 | 3 | 1.5 |
| 2016 |  Giravanz Kitakyushu has been relegated to J3, and Zweigen Kanazawa played and won their first promotion/relegation Series with the J3 runners-up, Tochigi SC. Oita Trinita is promoted from J3. | 22 | 3 | 1.5 |
| 2017 |  Starting this season, there are two promotions from and two relegations to J3.  Thespakusatsu Gunma is relegated to J3, Tochigi SC is promoted. | 22 | 3 | 2 |
| 2018 |  The promotion-relegation playoff is reintroduced, to be played as one match only.  Roasso Kumamoto and Kamatamare Sanuki are relegated, FC Ryukyu and Kagoshima United are promoted from J3 | 22 | 2.5 | 2 |
| 2019 |  Kagoshima United and FC Gifu are relegated, Giravanz Kitakyushu and Thespakusatsu Gunma are promoted from J3 | 22 | 2.5 | 2 |
| 2020 |  No relegations from J2. Blaublitz Akita and SC Sagamihara are promoted from J3 | 22 | 2 | 0 |
| 2021 |  SC Sagamihara, Ehime FC, Giravanz Kitakyushu, and Matsumoto Yamaga are relegated, Roasso Kumamoto and Iwate Grulla Morioka are promoted from J3 | 22 | 2 | 4 |
| 2022 |  FC Ryukyu, Iwate Grulla Morioka are relegated, Iwaki FC and Fujieda MYFC are promoted from J3 | 22 | 2.5 | 2 |
| 2023 |  Omiya Ardija, Zweigen Kanazawa are relegated, Ehime FC and Kagoshima United are promoted from J3  J.League abolishes entry playoff, reinstates promotion playoffs  League reduced to 20 clubs from 2024 since 2011 | 22 | 3 | 2 |
| 2024 |  The three worst-placed teams will be directly relegated to J3. | 20 | 3 | 3 |