The argument is that offal, which before the World War II had been either discarded or used as fertilizer, was grilled and eaten by Korean female factory workers in Japan and became what is now known as horumonyaki, and that therefore the custom of grilling offal (small intestine) originated not in Korea but Japan.
戦前に捨てるか肥料にするかしていた臓物肉を朝鮮人女工がもらってきて焼いて食べたのがホルモン焼きの始まりであり、ホルモンを焼いて食べる習慣は朝鮮にはなく、ホルモン焼きは日本で始まった。