The Matsuba-kai (松葉会) is a yakuza organization based in Tokyo, Japan. The Matsuba-kai is a designated yakuza group with an estimated 1,500 active members and 600 semi-active members.
The group was formed in 1936 in Sumida, Tokyo as a construction company named the Sekine-gumi (関根組) by bakuto Masaru Sekine. In 1946 they were involved in the 1946 Shibuya incident where they fought for control of the local black markets. The Sekine-gumi rapidly expanded, but in 1947 many members were arrested by GHQ for firearms possession, resulting in the group being forced into disbanding. The group officially restarted in 1953 with the name "Matsuba-kai". The Matsuba-kai was registered as a designated yakuza group under the Organized Crime Countermeasures Law in 1994.
Based in Asakusa, Taito, Tokyo, the Matsuba-kai has its known offices in nine other prefectures including Hokkaido. The Matsuba-kai is a member of a bakuto fraternal federation named the Kanto Hatsuka-kai, along with four other Kanto-based yakuza syndicates, the Sumiyoshi-kai, the Inagawa-kai, the Toa-kai, and the Soai-kai.
In the early 2000s the Matsuba-kai was involved in a violent feud with the rival Kyokuto-kai, which led to a number of shootings.
The gang gained some international prominence in early 2005, when it was revealed that the Urayasu-based cleaning company contracted to Tokyo Disney Resort was run by a member of the Matsuba-kai, Saburo Shiga. Another brush with fame came in the 1980s when the gang was caught smuggling 12 kilos of heroin into Canada.