KI3 is located on the medial aspect of the hock in the apex of the "V" formed by the fibular tarsal bone and the tibia.

Insertion 1 Tsun.
My Graphic
For practical purposes you should identify the fibular tarsal bone which is the prominent projection behind the hock and continuous with the achilles tendon.

Palpate on the medial aspect of the hock where the
fibular tarsal bone meets the tibia.

Note how the space between these two landmarks narrows to a "V".

Insert the needle parallel to the ground and to pass as close to the 2 bones as possible without touching either.
My Graphic