1Place chicken in a large pan; cover with cold water. Add leek, celery, carrot, ginger and salt. Bring to boil. Reduce fire; cook, uncovered, for 2 hours. Skim away any froth that rises to the surface.
2Drain and remove chicken from the stock; place on a plate. Stand until chicken is cool. Strain stock into a large pot; skim away the fat from the top. (You can make the stock a day ahead and refrigerate. The fat will solidify on the surface and is easier to remove).
3Discard chicken skin and shred the flesh coarsely. Set aside.
4Return 1.5 litres of stock to a large clean pot and bring to boil over a high fire. Add corn; turn fire to low and cook, uncovered, for 2 mins. Add chicken flesh to the pot with soy sauce; bring to boil again. Add noodles; cook over a low fire, uncovered, for about 3 mins.
5Ladle soup, noodles, chicken and corn into four serving bowls. Serve hot with coriander.
Photo: Bauer/Rob Shaw