Vinegar Mixture: 1/2 c rice vinegar,3/4 c sugar. 2 tbsp salt ajimoto..... combine and bring to boil. simmer 5-10 minutes.
Cook 6 c rice. Divide rice into 2 parts. Mix 1 tsp sugar, 1 tsp salt and 1/2 of vinegar mixture into each part (plus 1/8 tsp red food coloring into 1 part)of rice while hot. Set aside.
Tuna Mixture: combine the 2 cans tuna,4 TBSP sugar, 3 TBSP shoyu and ajimoto and heat in frying pan.
Line a 9x13 pan with 3 sheets of wax paper for strength. Put 1st part of rice (white rice) in pan and pat down. Spread the tuna mixture. Put 2nd part of rice (pink rice) on tuna and pat down evenly.Sprinkle to with colored shrimp flakes (optional)