Huo Ying and Huo Zhu are two points that are usually needled together on the Liver channel on the top of the foot. They are the Master Tung equivalent of Liver 2 and Liver 3, but they are located slightly differently.
Huo Zhu is at the base of the junction of the 1st and 2nd metatarsal bones. Needle as close to the junction as you can for best effect.