How to Make It
Trim the ends of the bok choy. Wash, pat dry with paper towels, and then set aside.
In a small saucepan add the soy sauce, sake, brown sugar, and rice vinegar. Heat and stir until the brown sugar is dissolved. Remove from heat and set aside.
Heat a large skillet or wok over medium-high heat. Add the oil and ginger. Cook ginger until soft and then add the bok choy. Cook for 1-2 minutes, or until the bok choy is just wilted.
Stir in the teriyaki sauce and tomatoes. Cook for another 30 seconds, or until heated through.