Soak bamboo skewers in water while you prep the rest of your food (at least 15 minutes).
Heat soy sauce, mirin, sake, and sugar in a pan over stovetop until sugar is dissolved and sauce is bubbling.
Leave sauce to simmer 5-10 minutes until you get a thin glaze.
Meanwhile, cut your chicken and onion into approximately 1.5 inch pieces.
Thread your skewers, alternating chicken and onion pieces.
Brush the chicken and onion with Mazola® Corn Oil.
Grill for 10 minutes or until chicken is almost cooked through (5 minutes per side).
Brush skewers with yakitori glaze and grill for another 3-5 minutes, until chicken is fully cooked.