Chicken and sweet corn soup

Name: Chicken and sweet corn soup
Prep time: 5 min
Cook time: 30 min
Total time: 35 min
Cuisine: American, Asian
Ingredients: 1 - 1 ½ cm piece fresh ginger, peeled; 120 g spring onions/shallots, trimmed and cut into pieces, plus extra for garnishing; 3 tsp olive oil; 1200 g water; 2 tbsp Vegetable stock paste (see Tips); 50 - 70 g tamari, to taste; 500 g skinless chicken breast fillets, cut into thin slices (6 x 1 cm); 300 g sweet corn cobs, kernels only