Place the chicken or chicken bones in a large pot. Add the halved onion, sliced ginger, and daikon radish (if using). Pour in 2 liters of water and bring to a boil over high heat.
Once boiling, reduce the heat to low, cover, and let the broth simmer for about 30 minutes. Skim off any foam or impurities that rise to the surface.
After 30 minutes, strain the broth to remove the solids. Return the clear broth to the pot. Season with salt, and set aside.