Mutsuo Hidaka, a former Ozeki in sumo wrestling, died on the 15th of pneumonia at the age of 69. He was well-known for his slender physique and earned the nickname 'Black Leopard of Nankai'. Having trained in the legendary Futagoyama stable under the first Yokozuna Wakanohana, he achieved the rank of Ozeki after the Kyushu tournament in 1982 and took home two championships in the top division. In 1985, he married popular singer Mizue Takada and retired from active competition in 1987, upon which he adopted the elder name Matsukane and later established his own stable. He mentored several notable wrestlers, including former Sekiwake Matsuhōzan and current Makunouchi wrestler Yamamoto. Throughout his career, as a member of the Sumo Association, he held significant roles, including Director of the Judging Department. Hidaka was part of the era dominated by famed Yokozuna Chiyonofuji, nicknamed 'Wolf', and his own skills in executing techniques like lifting and thrusting from a left-side position made him a notable competitor. His personal life was equally vibrant as he shared it with his pop singer wife, experiencing life's successes and challenges in tandem.