Why is there no Buddhist idols ? What is the Gohonzon?

Buddhism is established by Shakyamuni Buddha (the historical Buddha). He left his ‘teachings’, or his understanding of the way of life, to his disciples and entered into nirvana. His disciples gathered all the teachings that Shakyamuni Buddha had taught during the 50 years and complied into 84,000 sutras. As the amount was enormous, different disciples held different views. They each focused on certain main points and developed into the various Buddhist schools.
From the disciples of Shakyamuni Buddha, the followers of the Buddha dared not hope to be able to attain enlightenment as their mentor. They began to regard becoming a Buddha as an unattainable position, even worship idol forms of the Buddha. They were satisfied if they would be able to become an arhat, one worthy of respect. For the lay believers, facing the enormous amount of sutras, it was even more difficult for them to comprehend. They made Buddha statues or idols as their object of prayers or as observation of Buddhist thinking.
However, the essence of Buddhism is to “open” the people’s mind in their understanding of their possession of the innate Buddha nature, which is inherent in all life. They could attain enlightenment by exerting themselves in both faith and practice, with the Buddha as their role model. Based on the fundamental teachings of Buddhism, Nichiren Daishonin taught that one could not attain enlightenment or open the path to true happiness by worshiping an external Buddha figure. Buddhism basically teaches all living being is to seek happiness from within oneself by realizing our innate Buddha nature and self-improvement in order to attain enlightenment.
The Gohonzon (object of worship) which Nichiren Daishonin had inscribed is the mandala that is fully endowed with the mutual possession of the ten worlds, which is the manifestation of the entity of life. People in the Latter Day can bring forth our innate Buddha nature through the practice of chanting Nam-myoho-renge-kyo and by fusing with our innate Buddha wisdom.