Slice the onion thinly. Remove the stems from the cherry tomatoes. Mince the garlic after removing its core.

In a bowl, mix the oysters with potato starch. Gently wash with water until the water runs clear. Drain and pat dry with a paper towel.

Heat olive oil and garlic in a pan over low heat until fragrant. Add the onion and sauté until softened.

Add the oysters, cherry tomatoes, black olives, and the seasonings (sake, salt, pepper, water). Cover and simmer over medium-low heat for 6-7 minutes.