Picture the Gohonzon as an organism

The Buddha and Nichiren taught the Three Treasures and the Three Great Secret Laws  and to keep in mind that the Treasure of the Law and the Secret Law of Namu Myoho renge kyo reigns supreme.

We can picture the Gohonzon as an organism with Namu Myoho renge kyo as the brain and spinal cord [central nervous system]. Although the brain and spinal cord is the master organ that controls all the other organs in order to assure that they perform properly and harmoniously, the organism will die without a heart, liver, or lungs. Lord Shakya of the Original Doctrine is the heart. 

Removing Lord Shakya of the Original doctrine from the Gohonzon is like removing the heart from a person. It will lose its beneficent function as a father whose heart dies loses his ability to support his family.