At first fighting under his real name, he took on the shikona of Mienoumi in July 1966, but did not adopt the Tsuyoshi given name until September 1976. After being personally trained by the new Dewanoumi Oyakaya, former yokozuna Sadanoyama, he developed his technique and was promoted to the jūryō division in March 1969, and makuuchi, the top division, in September 1969. In July of the following year, he reached the rank of komusubi, defeating two yokozuna (Taihō and Tamanoumi) and receiving his first prize for Outstanding Performance.
Initially competing under his genuine name, he adopted the ring name Mienoumi in July 1966, but didn't take on the surname Tsuyoshi until September 1976. After being personally trained by the new Dewanoumi Oyakaya, former yokozuna Sadanoyama, he refined his style and was promoted to the jūryō division in March 1969, and makuuchi, the top division, in September 1969. A year later, in July, he achieved komusubi rank, defeating two yokozuna (Taihō and Tamanoumi) and receiving his first prize for Outstanding Performance.