In a pot, combine katsuo soy sauce (or tsuyu), water, sugar, vinegar, and minced garlic.

Add sliced onion to the pot and bring to a boil.

Cook until the onion becomes soft and translucent. It's okay if the liquid reduces significantly.

Place cooked rice in a bowl.

Top the rice with the cooked onion.

Layer fresh salmon slices neatly over the onion.

Add more sliced onion on top and finish with a dollop of wasabi.