Cover the beans with 5 cups of cold water in a large bowl and soak for 8 hours.
Drain and rinse the beans. Place them in a large skillet with the soy sauce and 2 cups of water. Cover and cook over medium-high heat for 30 minutes. If the water foams, adjust the lid to be partially covered and stir occasionally.
Add the garlic, brown sugar, and rice syrup. Mix well, then turn the heat to low and simmer, covered, for 30 minutes.
Uncover and stir with a wooden spoon. Increase heat to medium-high and cook for about 3 minutes until the beans are shiny, sticky, and slightly wrinkly. Remove from heat, transfer to a bowl, and sprinkle with toasted sesame seeds.