1. In a large pan, add the minced pork and stir-fry until no longer pink. Combine all seasoning for minced pork, sake, soy sauce and sugar and mix well. Put it aside to let it cool.
2. Sift flour into a large bowl, and then add water and egg to mix. Stir constantly to keep lumps from forming.
3. Add all vegetable (carrot (optioanl), leek and cabbage), sauteed minced pork, all ingredients for the seasoning of batter gradually and mix together well.
4. Heat up a frying pan with 1 tbsp oil, spoon the okonomiyaki mixture on it and spread it into a round shape of about 1 to 1.5cm thickness. Well, it doesn't really need to be so round if you want. Fry over medium heat until the bottom side becomes golden brown, then turn it over with a spatula and press down on the okonomiyaki to compress. Fry it uncovered until the other side is browned.
5. Mix all sauce ingredients (chuno sauce, ketchup and white sugar), mix well.
6. Transfer the okonomiyaki to a plate, put sauce and mayonnaise (to your taste) on it.