Beef yakitori skewers

Name: Beef yakitori skewers
Prep time: 3 h 25 min
Cook time: 10 min
Total time: 3 h 35 min
Cuisine: Asian, Japanese
Ingredients: 40.00 ml sake (see note); 42.00 gm dark soy sauce; 10.00 gm mirin seasoning; 20.00 gm caster sugar; 2cm piece fresh ginger, finely grated; 800g beef rump steak, trimmed, cut into 3cm pieces; 4 green onions, cut into 3cm lengths; 123.75 gm Kewpie mayonnaise; 1 tsp wasabi paste