Liuhe, the six harmonies are

1. Shou Yu Zu He - Hands (Shou) harmonize with feet (Zu)
2. Jian Yu Kua He - Shoulders (Jian) harmonize with hips (Kua)
3. Zhou Yu Xi He - Elbows (Zhou) harmonize with knees (Xi)
4. Xin Yu Yi He - Heart (Xin) harmonizes with intent (Yi)
5. Yi Yu Qi He - Intent (Yi) harmonizes with vital energy (Qi)
6. Qi Yu Jin He - Vital energy (Qi) harmonizes with internal force (Jin)

To be effective and powerful, these principles must be followed, regardless of the style you practice. Liuhe has to be experienced, thinking about it too much does not help.