If you propagate it, devils will arise without fail. If they did not, there would be no way of knowing that this is the correct teaching.
(The Writings of Nichiren Daishonin, Vol.1, p.501)

Fundamental to the Buddhist view of life is the recognition that both positive and negative energies are innate within all people. To win in life, the positive potential we possess must predominate over the negative. Buddhism characterizes this struggle for the dominance of our innate goodness over innate evil as that between the "Buddha" and "devils." The wisdom of faith allows us to bring forth our enlightened potential, while recognizing negative, or devilish, functions and diminishing their influence.

Defeating the devilish nature within human life, which is the cause of much suffering and injustice in the world, is the original purpose of the Buddha's teachings. Great philosophies throughout history have shared this goal. The great 20th-century historian Arnold J. Toynbee has stated to the effect that the human soul is a spiritual battleground, in which good and evil struggle endlessly for control. The Buddhism of Nichiren Daishonin elucidates the highest and most powerful method for winning over devilish functions in life, enabling our essential goodness to prevail.

In his work Great Concentration and Insight the Great Teacher T'ien-t'ai of China expounded a method for Buddhist practice for realizing the ultimate Buddhist principle, which he called three thousand realms in a single moment of life. He called this practice "observing the mind"-a form of contemplation for perceiving the Buddha nature within one's own life. He explained that as one advances in Buddhist practice, functions that aim to obstruct this practice will emerge from the depths of one's life and interfere. T'ien-t'ai referred to these functions as "the three obstacles and the four devils" to describe the different forms in which they appear. The most fundamental of these is referred to as the devil king of the sixth heaven.

But Nichiren explained these functions in a broader and more concrete way. Earlier in this letter, he writes, "This world is the domain of the devil king of the sixth heaven." (The Writings of Nichiren Daishonin, vol. 1, p. 495). Kosen-rufu-the broad spread of the Mystic Law for the creation of a peaceful world-is nothing other than the struggle to wrest control of this world away from the evil tendencies of life, the devil king, and to build a "Buddha land," a world in which people fully express and enjoy their enlightened nature.

In other words, while T'ien-t'ai viewed the field of struggle between our Buddha nature and devilish functions as the inner world of the human mind alone, Nichiren viewed it as extending into the whole of the real world. The practice these functions oppose is not merely inward contemplation, but efforts to practice and spread Nam-myoho-renge-kyo-the essential Law capable of securing peace and happiness for all humanity.

Though Nichiren spoke of devils or the devil king, it is important to understand that he did not view these as actual specific beings or entities, like the Christian devil, or Satan. Nichiren says, "The fundamental darkness manifests itself as the devil king of the sixth heaven" (WND-1, 1113). Fundamental darkness refers to deep-seated ignorance-ignorance of the sublime Buddha nature all people possess.

In its strongest form, the function of this devil appears in the form of a person who opposes Buddhism. Most often, it assumes the form of the devilish aspect of power-in the thoughts and actions of those with political or religious power to oppress or persecute people of wisdom who try to spread the correct Buddhist teaching. Hei no Saemon and the priest Ryokan of Gokuraku-ji temple, who persecuted Nichiren, fit this mold. The machinations of these individuals lay behind harsh persecutions of Nichiren's followers, including the Ikegami brothers, to whom "Letter to the Brothers" is addressed.

	Sometimes it's hard to know that we are being swayed from our Buddhist practice or from making efforts for kosen-rufu. How can we develop the wisdom to perceive such obstacles as obstacles?
	Why is it important to identify and face obstacles?

Nichiren says: "The single word 'belief' is the sharp sword with which one confronts and overcomes fundamental darkness or ignorance" (The Record of the Orally Transmitted Teachings, pp. 119-20). Devilish functions arise in response to efforts to persevere in and spread the correct Buddhist practice. It may take the form of jealousy and resentment toward the strength and joy expressed by Buddhist practitioners. The method of defeating such devils lies in continually challenging ourselves to believe in the world of Buddhahood inherent in the life of every human being. When we pray and carry out dialogue to defeat the negativity in our own lives and the lives of others and to respect and bring forth our Buddha nature, we will drive away the dark clouds of illusion that obscure our lives and cause the sun of Buddhahood to shine brilliantly from within. This is what it means to attain Buddhahood.