The four remaining chefs board an American Airlines flight and travel to Tokyo, Japan. The chefs begin a culinary adventure into the world of umami (a Japanese term for 'delicious' that is used to describe the fifth taste). First the chefs arrive at a traditional Japanese yakitori grill restaurant where they are asked to use Kikkoman soy sauce to infuse umami into their dishes and enhance the flavor profiles of a variety of ingredients. Iron Chef Masaharu Morimoto arrives as a surprise judge for this test. Then the chefs travel through Tokyo to the most renowned culinary academy in the city where they meet Dr. Yukio Hattori, the original Iron Chef Japanese culinary commentator. Dr. Hattori opens the doors to his academy where the chefs are challenged to use different cooking styles in a test that highlights the five tastes: sweet, salty, sour, bitter, and umami. The next chef is eliminated.