Japanese griddle cooking encompasses two distinct traditions: okonomiyaki (savoury cabbage pancakes from Osaka and Hiroshima, each with fundamentally different technique) and teppanyaki (iron griddle cooking of meats, seafood, and vegetables). Okonomiyaki literally means 'grilled as you like it' — a batter-based dish customised with toppings, finished with a specific constellation of sauces. The Osaka style mixes everything into the batter. The Hiroshima style LAYERS everything — noodles, cabbage, egg, protein — building from the bottom up. They are different dishes sharing a name.
Osaka-style: shredded cabbage folded into a light batter (flour, dashi, egg, grated nagaimo/yamaimo for fluffiness), with chosen additions (pork belly, shrimp, squid, cheese). Cooked on a hot griddle, flipped once. Hiroshima-style: a thin crêpe of batter on the griddle, topped with a mountain of cabbage, bean sprouts, pork belly, then flipped so the cabbage steams under the crêpe. Yakisoba noodles are cooked alongside and the stack is assembled layer by layer. Finishing for both: okonomiyaki sauce (similar to Worcestershire but sweeter and thicker), Kewpie mayonnaise in a crosshatch pattern, aonori (green seaweed flakes), and katsuobushi (bonito flakes that dance in the heat).
The secret ingredient is nagaimo (mountain yam) — grated into the batter it creates extraordinary lightness and fluffiness. Dashi in the batter adds umami depth. For teppanyaki: the flat iron griddle's even heat is the technique — no hot spots, no flame. Wagyu beef is sliced thin and cooked for seconds. Garlic chips are fried in butter on the griddle and scattered over everything. The teppanyaki chef's knife skills are performance art — precision cutting at speed on a hot surface.
Pressing the okonomiyaki flat — let it be thick and fluffy, don't compress it. Mixing too vigorously — fold the cabbage into batter gently. Using regular mayonnaise instead of Kewpie — the egg yolk richness and MSG are distinctive. For Hiroshima-style: assembling everything at once instead of building layers sequentially. Not enough cabbage — it should seem like far too much before cooking, then wilts to the right proportion.