	In the early 40s he wrote lyrics mainly to American swing classics (George Gershwin, R. Rodgers, D. Ellington, H. Carmichael et al.). During the occupation the Nazis condemned it as "Jewish-Bolshevik filth", which was nevertheless played among the youth, particularly on tramping meetings. Kainar put some of his texts to music himself—e.g. the songs "Černá kára", "Starý mrtvý vrabec", "Blues železničního mostu". He also wrote the lyrics to the jazz rock masterpiece "Kure v Hodincach", published by the rock band Flamengo in 1971.