Rubuta ci gaba don wannan sakin layi - A ranar 13 ga Agusta, 1971, lokacin da Nagai ke da shekaru 19, ya fara bugawa tawagar kasar Japan wasa da Iceland. Ya kuma taka leda a wasannin Olympics na 1972 a shekarar 1971. Kodayake, bai buga wa Japan wasa ba a 1972, an zaɓe shi Japan don cancantar gasar cin kofin duniya ta 1974 a 1973. Ya kuma taka leda a 1974
, Wasannin Asiya na shekarar 1978. A shekarar 1980, an zaba shi Japan don cancantar wasannin Olympics na bazara na 1980, rashin nasarar Japan don cancantar wasannin Olympics na bazara na 1980. Wannan cancantar ita ce wasan sa na karshe ga Japan. Ya buga wasanni 69 kuma ya ci kwallaye 9 don Japan har zuwa 1980.