In a large bowl, combine soy sauce, water, brown sugar, and oil.
Use a microplane to grate the garlic cloves and ginger, or mince them with a knife. Add to the sugar mixture.
Gently cut the steak into square pieces, then place them in the marinade. Cover with plastic and transfer to the fridge to let them marinate for at least 6 hours or overnight.
Before cooking the beef, soak the skewers in water for 30 minutes (this will prevent them from burning while in the oven).
Preheat oven to 350°F (177°C). Pierce the pieces of beef on the skewers, then place on a parchment-lined baking tray. Cook in the oven for a total of 30 minutes, rotating the skewers every 10 minutes. Let cool slightly before serving.