The title of the series is ISAN: NO FOOTPRINTS IN THE BLUE SKY. He was as great a master as one can be, but has left behind him neither great scriptures nor great commentaries. Isan functioned exactly as Buddha had said an authentic master would — to disappear in the blue sky like a bird, leaving no footprints.
Why this idea of leaving no footprints? It has great implications in it. It means a great master does not create a following; he does not make a path for everybody to follow. He flies in the sky, he gives you a longing for flying, and disappears into the blueness of the sky — creating an urge in you to discover what it is like to disappear into the ultimate.
Isan followed exactly what Buddha had said. He is a great master, but almost forgotten. Who remembers people who have not created great followings, who have not made organized religions, who have not chosen their successors, who have not made their religion a politics, a power in the material world? Isan did none of that. He simply lived silently. Of course thousands of disciples were attracted towards him, but it was not his fault. You cannot blame him for it — it was just the magnetic force that he had become by disappearing into enlightenment. The light shone to faraway lands and those who had eyes started moving towards a small place hidden in the forest where Isan lived. Slowly slowly, thousands of disciples were living in the forest — and Isan had not called a single one. They had come on their own.
– Isan: No Footprints in the Blue Sky, Chapter #1
Isan was very polite. Naturally his politeness would affect whatever happened around him. He was a very humble person, never tried to convert anybody, but on the contrary slipped deep down into the forest, so nobody came to him. He felt it a little embarrassing to be the master and degrade somebody as a follower — a very nice, very delicate personality, the personality of a poet, of a singer, of a dancer.
– Isan: No Footprints in the Blue Sky, Chapter #3
Choosing Kyozan as his successor, and waiting for forty years — what patience! — almost transforming a stone into a diamond. But Isan was determined to make one point absolutely clear to humanity: if Kyozan, a simple and ordinary person, not belonging to any speciality, any category, without any talent, any genius — if he can become enlightened, it will be a proof. To give this proof to humanity he chose Kyozan and worked hard on him. And the day Kyozan became enlightened, the day Isan transferred his enlightenment and the two flames became one, Isan disappeared from the world of matter, body, mind.
Kyozan was so radiant now. He was not only once enlightened, he was twice enlightened. His master has given him richer experiences, far deeper spaces, far clearer skies.
– Kyozan: A True Man of Zen, Chapter #1