Stir the soy sauce, mirin, sake, sugar, and ginger together. That is teriyaki. No cornstarch, no garlic powder, no bottle.
Pat the salmon dry. Dry skin is the entire secret to crispy skin.
Heat the oil in a nonstick pan over medium-high. Lay the salmon in skin side down and do not move it for 4 minutes. Press gently with a spatula for the first 30 seconds so the skin stays flat.
Flip, cook 2 minutes, then pour in the sauce. Let it bubble and reduce for 2 to 3 minutes, spooning it over the fish as it thickens.
Meanwhile, roast or pan-char the broccoli with a pinch of salt.
Serve over rice, glaze spooned on top, skin side up so it stays crisp.