In a saucepan, bring 2 cups of water to a boil then add soaked rice. Soak rice for 4 hours before using; drain and rinse well.

Reduce heat, cover, and simmer for an additional 20 minutes.

When rice is cooked, stir in vinegar and let cook for 30-60 minutes. The rice should be at room temperature before assembling musubi.

To make the spam marinade, stir together soy sauce, oyster sauce, and sugar until completely dissolved. Then add sliced spam to the marinade. Let marinate for 5-30 minutes (the more time the better). This will give the spam a nice caramelized flavor.

Sautee spam slices with oil in a large skillet over medium-high heat. Cook 2 minutes per side until browned.

To assemble musubi, you can either use a spam musubi moldor use your hands to create a mold. Using the sliced spam as a guide, form a rice patty of the same shape. Then wrap the rice and spam with a nori seaweed stripe. Use water to seal seaweed.