Forum:I need help with a judge question about chain

Well this happend 3 days ago in one no official tournament in my first turn I put facedown in my magic/trap zone 1 karma cut and 1 infernity inferno and to finish my turn I just summon 1 stygian street patrol and in the turn of my opponet he special summon 1 elder of the six samurai and normal summon 1 kagemusha of the six samurai and in that moment I activate my karmna cut and he say that I cant do that because the normal summon don´t start a chain and I can´t activate my trap cards until he start a chain or in the end phase is that truth or my opponent understand the main phase rule