Slice the chicken meat diagonally into
bite-sized pieces.
In a saucepan, combine the sake and soy sauce
and bring to a simmer. Add the chicken meat and cook gently for approx. 3 minutes until it
is tender. Keep hot.
Bring chicken stock to a boil and add leek and
simmer for 3 minutes, then add the spinach.
Remove from the heat and keep warm.
Cook the noodles in a large saucepan of boiling
water until just tender (follow the manufacturer's directions on the packet).
Drain noodles and divide equally among serving
bowls.
Ladle the hot soup into the bowl, then add a
portion of chicken to each.
Serve immediately, garnished with toasted sesame
seeds.