I was looking for a right cover crop with rice, wanted to try white clover which Fukuoka san had tried, but two times seed didn't even germinate. Recently got seeds of white clover, yellow clover and crimson clover and one more (to be identified), in exchange with Happy Hill rice seeds and to my surprise all of them germinated.
They couldn't survive the harsh summer, none of them flowered also, have some spare seeds will try them at the beginning of the next rainy season