Satoru Sayama (佐山 聡, Sayama Satoru; born November 27, 1957), best known as the original Tiger Mask, is a Japanese writer, semi-retired professional wrestler and martial artist, and mixed martial arts (MMA) and wrestling promoter and trainer. He is the founder of Shooto, a pre-UFC MMA promotion, and is widely considered to be one of the most influential masked Japanese wrestlers of all time (alongside his contemporaries Jushin Thunder Liger and Último Dragon). The only man to hold the WWF Junior Heavyweight Championship and the NWA World Junior Heavyweight Championship simultaneously, Sayama became widely known in the wrestling world for his all-round prowess of high-flying, technical abilities, and martial combat skills (as he was a practitioner of judo and freestyle wrestling in his youth).

Primarily trained under New Japan Pro-Wrestling (NJPW) founder Antonio Inoki and his mentor Karl Gotch, Sayama made his professional wrestling debut in 1976 at 18 years old. He was sent on an excursion to Europe for World of Sport (WOS), and Mexico for EMLL, where he not only found his ground as a technical wrestler, but also found his niche in Lucha libre. Sayama became Tiger Mask in 1981, brought from Ikki Kajiwara's 1968 manga series of the same name and the popular anime of the decade. He became involved in highly publicized feuds with Black Tiger (portrayed by Mark Rocco), the Dynamite Kid, and Yoshiaki Fujiwara, who was one of Sayama's own trainers. He left NJPW at the height of his popularity in 1983 due to political disenfranchisement, and later became a founding member of the UWF brand in Japan. He then became dissatisfied with wrestling as a whole, leading him to write Kay Fabe (1985), which detailed the kayfabe and secrets of puroresu at the time.

After declaring retirement from professional wrestling in 1985 after the collapse of UWF, he founded Shooto, one of the first MMA organizations in the world. Sayama also started mixed martial arts training and developed his own Shooto syllabus for learning what could be considered the first put together MMA training of its kind, with a focus on striking from arts like boxing, muay thai, and karate, and grappling from wrestling, judo, and sambo. The curriculum would help produce the first well rounded fighters of MMA several years before the first UFC event. While on Shooto, Sayama promoted the Vale Tudo Japan events, more rules free events inspired by Brazilian Vale Tudo and early UFC, helping to popularize MMA in Japan. He retired from his post in Shooto in 1996, and returned to professional wrestling soon after.

In 2005, Sayama founded his own promotion, Real Japan Pro-Wrestling (RJPW), which later became Strong Style Pro-Wrestling. Sayama likened the promotion to include wrestlers from the past, as well as martial artists, Sayama's students, and modern stars from the likes of Battlarts, Big Japan Pro Wrestling (BJPW), and more. Although he hasn't officially declared retirement, Sayama last wrestled on December 7, 2016. It was announced in 2020 that he had several health problems, possibly linking him to Parkinson's disease and immobility.

Sayama debuted in New Japan Pro-Wrestling, against Shoji Kai (Kanji Kitazawa), a jobber known to have been the debut opponent for future stars (Rusher Kimura, Masa Saito, Osamu Kido, Tatsumi Fujinami, and Mitsuo Momota had debuted against him before). Sayama weighed only 160 pounds, which, even given his training, impaired him from getting a permanent spot on NJPW cards. So they sent him abroad, to England where wrestling as Sammy Lee, he took on opponents such as Mark Rocco and Mick McManus as well as teaming with Big Daddy. He also had a stint in Mexico, where he wrestled under his real name. It was in Mexico where he started to grow not only in physical stature but also in prominence, winning the NWA World Middleweight Championship in EMLL.

In 1981, NJPW was looking for a way to attract young fans to its wrestling. They looked to the popular Tiger Mask anime and created a wrestling character called Tiger Mask for the fans, with the recently returned Sayama playing the role. On the evening of Thursday, April 23, 1981, Satoru Sayama made his way to the ring in the Kuramae Kokugikan as Tiger Mask. Initially, many traditional Japanese fans scoffed at the thought of artist Ikki Kajiwara's popular comic book wrestling hero being pushed as a legitimate wrestling star, but he shocked the Japanese fans in the arena by pinning Dynamite Kid with his German suplex. As a result, he was immediately regarded as the premier star in New Japan's junior heavyweight ranks. Moreover, that match would be the first of many classic battles between the two men.

On May 6, 1982, Tiger Mask was forced to vacate the WWF Junior Heavyweight Championship after injuring his right knee. Tiger Mask would go on to win the NWA World Junior Heavyweight less than 3 weeks later on May 25, 1982. The next day, Tiger Mask defeated old UK rival Mark Rocco, wrestling in the guise of Black Tiger, in a match for the WWF Junior Heavyweight title. This victory was met with controversy, as some board members on the NWA declared the title vacant, as they felt that the NWA World Junior Heavyweight Championship was the premier title for the division. However, during an annual meeting between the NWA and New Japan Pro-Wrestling, it was declared that Tiger Mask was still recognized as the official champion, which made him the only man to simultaneously hold the NWA World Junior Heavyweight Championship and the WWF Junior Heavyweight Championship.

Around this time, Sayama trained in sambo under Victor Koga and kickboxing under Toshio Fujiwara.