Before you start, bring a large pot of salted water to the boil with the lid on.
In a small bowl, combine teriyaki sauce, soy sauce and water measure together and set aside. Prep broccoli, courgette, bok choy and spring onion and set aside separately.
Heat first measure of sesame oil in a large fry-pan on high heat. Cook broccoli and courgette for 5-6 minutes, tossing occasionally, until tender. Remove from pan and set aside. Return pan to high heat and cook bok choy, spring onion and edamame for 3-4 minutes, until bok choy is tender.
Return broccoli and courgette to pan, along with teriyaki sauce mixture. Toss together and cook for a further 1 minute, until hot through. Season to taste with soy sauce.
Meanwhile, cook soba noodles in pot of boiling water on high heat for 4-5 minutes, until tender. Drain and refresh under warm water. Return to pot with second measure of sesame oil to prevent sticking.
To finish, prep chives.
Serve soba noodles and stir-fry topped with Japanese mayo, chives and sesame seeds.