The Green Seat is the first episode of the anime series.
A boy named Shinra Ioroi has the ability to create life by drawing with his left hand. While attempting to write a letter, the Japanese kanji come to life as they were originally symbols meant to represent pictures. The symbol for bird flies outside and is caught by Ginko, who had sent Shinra a letter before arriving asking if he could investigate the boy's ability. However, Shinra tries to turn Ginko away due to his late grandmother's final wish of Shinra keeping his gift a secret and using it as little as possible, as she believed that creating life should be left to God.
His grandmother, Renzu, refused to let him leave their house in the woods, most likely because people would never let him live in peace due to his power. Shinra tells Ginko about the creatures he can see, and how his grandmother dismissed them as illusions born of his powers. Ginko explains that the things Shinra sees are known as Mushi, creatures that exist outside the classifications of humans, plants and animals, closer to being mere essenses of life than anything else. Ginko explains that their shapes and existences can be vague, and that some can even pretend to be human.
Though Shinra refuses to allow Ginko to investigate, he still offers for Ginko to stay the night. That night, Ginko discovers a ghost-like Mushi in the form of a young girl and uses his Mushi tobacco to subdue her, discovering a broken green wine cup in her possession. From this, he determines that the ghost is really Shinra's grandmother, Renzu.
The next morning, Ginko explains to Shinra that Renzu is still in the house, though she currently exists in a state in-beween the human and Mushi realms. She became this way via a Mushi Banquet, a rare occurence wherein Mushi pretend to be human and invite a human guest to drink with them. When the human drinks the whole cup, they lose their identity as a sentient being and come to inhabit the Mushi world. Renzu had only drank half of the cup when her ceremony was interrupted, causing her spirit to split in half, one half remaining in the Mushi world while the other half returned to the physical world. Despite this split, the Mushi half remained near her physical half, watching over Shinra even after her physical self died four years ago.
Ginko offers them a way to turn Renzu into a full Mushi, which would allow Shinra to be able to see her but would also prevent her from ever being human again. Renzu agrees immediately, tearing up at the thought of being able to properly meet with Shinra, and Shinra agrees to help. The process involves Shinra drawing the wine cup; using only his imagination, he is able to perfectly replicate it. The drawing then comes to life in the form of a real, physical wine cup, identical to the one Renzu drank from, and proceeds to split in half. Ginko takes his half of the real cup and combines it with half of the cracked drawing, forming a completed cup. The cup fills with wine and Renzu takes a sip, completing her Mushi form. Shinra blushes at the sight of her, embarrassed and caught off guard by the fact his grandmother looks like a child in this form. After teasing him, Ginko prompts him to drink from the sake cup as well.
When Shinra drinks it, he sees a memory of the Mushi banquet that Renzu attended. He learns that the Mushi told her that the sake she drank was kouki, liquid from a river of light that has existed since the beginning of life itself, and that she was invited there because the Mushi had a request. They explained that she would one day have a grandson with a unique ability, one that may change the entire living world, and that they needed her to look after him. However, the banquet was interrupted by a crow, and her Mushi self was left behind with the unfinished banquet, crying silently to herself. Shinra finds himself crying as well, overwhelmed with Renzu's emotions. As if in sympathy, the sake cup overflows with kouki as well, spilling out onto the forest floor and causing moss to grow abundantly.
Ginko leaves the following morning, though he is confronted by Renzu before he goes. She asks if he plans to continue his investigations and says that if not, he should stop by sometime, as Shinra will probably be lonely by himself. Ginko responds that Shinra should be fine since she is there to watch over him now. When he leaves, he takes the green sake cup with him. Since then, there have been no more rumors about the boy's powers.
- Not only is this the first episode of the anime, it is also the first chapter of the manga.
- Shinra starts his letter by talking about the season; this is a common zenbun, or preamble, used when writing a traditional Japanese letter. Typically, it is 5-6 lines referring to the current season or situation. The expressions themselves are so cliche you can search for them in letter dictionaries rather than needing to come up with your own. In this case, Shinra was likely taught by his grandmother.