The Japanese word Sosai (Japanese:総裁, "Sōsai") means roughly "president" or "director-general". It is used in several ways:

Political

• Sosai, or president of the government, was only once the title of the imperial prime minister: from 1 January 1868 (before there was no cabinet, only chief advisers: Kampaku
  Sessho and Kampaku
  In Japan, was a title given to a regent who was named to assist either a child emperor before his coming of age, or an empress. The was theoretically a sort of chief advisor for the emperor, but was the title of both first secretary and regent who assists an adult emperor. During the Heian era,...
  
  to the nominally reigning Tenno
  Emperor of Japan
  The Emperor of Japan is, according to the 1947 Constitution of Japan, "the symbol of the state and of the unity of the people." He is a ceremonial figurehead under a form of constitutional monarchy and is head of the Japanese Imperial Family with functions as head of state. He is also the highest...
  
   (emperor) and both Rōjū
  Roju
  The ', usually translated as Elder, was one of the highest-ranking government posts in Tokugawa Japan. The term refers either to individual Elders, or to the Council as a whole; under the first two shoguns, there were only two Rōjū...
  
  and Tairō
  Tairo
  Tairō was a high-ranking official position in the bakuhan taisei government of Japan. The tairō would preside over the governing Rōjū council in the event of an emergency. A tairō would be nominated from among a group of samurai families who supported Tokugawa Ieyasu...
  
  to the de facto ruling Shogun
  Shogun
  A was one of the hereditary military dictators of Japan from 1192 to 1867. In this period, the shoguns, or their shikken regents , were the de facto rulers of Japan though they were nominally appointed by the emperor...
  
  ) until 11 June 1868: Prince Taruhito Arisugawa (1835–1895); next the prime ministerial office is styled U Daijin "Ministers to the Right", in 1871 shortened to Daijjin.

• Sosai also was the title of Admiral Takeaki Enomoto (1836–1908), the elected president (27 January 1869–27 June 1869) of the short-lived rebellious Ezo Republic on the present Hokkaidō Island
  Hokkaido
  , formerly known as Ezo, Yezo, Yeso, or Yesso, is Japan's second largest island; it is also the largest and northernmost of Japan's 47 prefectural-level subdivisions. The Tsugaru Strait separates Hokkaido from Honshu, although the two islands are connected by the underwater railway Seikan Tunnel...
  
  , vanquished by Imperial troops.

• Sosai, or President of Liberal Democratic Party
  Liberal Democratic Party (Japan)
  The , frequently abbreviated to LDP or , is a centre-right political party in Japan. It is one of the most consistently successful political parties in the democratic world. The LDP ruled almost continuously for nearly 54 years from its founding in 1955 until its defeat in the 2009 election...
  
  , is the office of the head of the LDP.

Others

This office also exist in various sports, in particular budō

Budo

is a Japanese term describing martial arts. In English, it is used almost exclusively in reference to Japanese martial arts.-Etymology:Budō is a compound of the root bu , meaning war or martial; and dō , meaning path or way. Specifically, dō is derived from the Buddhist Sanskrit mārga...

, business and charitable organizations. The term is also used to translate the head of various foreign organizations.

The most famous of such people is Sōsai Ōyama Masutatsu, who earned this appellation by creating a karate

Karate

is a martial art developed in the Ryukyu Islands in what is now Okinawa, Japan. It was developed from indigenous fighting methods called and Chinese kenpō. Karate is a striking art using punching, kicking, knee and elbow strikes, and open-handed techniques such as knife-hands. Grappling, locks,...

 style called Kyokushin

Kyokushin

is a style of stand-up, full contact karate, founded in 1964 by Korean-Japanese karate master, who was born under the name Choi Young-Eui . Kyokushinkai is Japanese for "the society of the ultimate truth". Kyokushin is rooted in a philosophy of self-improvement, discipline and hard training...

kai and spreading karate in the western world.