Disclaimer: Hikaru no go belongs to persons and companies not myself.
For Wanting Nails
If it were to be that at the end of every life you get one wish, one small thing to have changed and rewind time for, and that and all it effects becomes the truth you moved through; if that wish were to be, this is his:
When Sai first has a premonition of his disappearance, somehow he manages to make his concerns clear to Hikaru. At first Hikaru refuses to believe it. But Sai's persistence manages to infect Hikaru as well, until he's so dreading Sai's absence, he takes back every criticism or complaint he ever had about the nuisance of being haunted, and he thinks he might fall off the world from this too.
But forewarned is forearmed. Prepared and braced.
Well then, if that is to be….
With the rising panic of mortals facing the inevitable, they make plans.
Our countermeasures shall become….
First Hikaru cancels all his matches, making some familial excuse. Next, they leave as soon as possible to a remote spot: Shiogama, Sai has decided. A place he's never been. Matsushima, and Hikaru makes arrangements at a hostel that won't ask too many questions about a teenaged boy traveling on his own. They take the Shinkansen on one ticket up, and every morning with the dawn they go out with a go board, and don't return until late at night. Stones are placed, and there is conversation, inconsequential and otherwise.
Although it is a tourist location, it is remote enough to hide in. Hikaru mentions that, for one of the Three Scenic Locations, it's not as crowded as he had expected. Sai tells him that in his time, it wasn't necessarily ranked quite that high, but it was famous.
There was a garden, he says. It was supposed to replicate this spot perfectly. They'd hire people to pretend to be fisherfolk and make salt to add atmosphere to poetry gatherings.
Eh, Hikaru says, and he's impressed. And was it just like here?
Sai shrugs. He's smiling, but it''s tense, and he doesn't look up from directing the board. It was a long time gone, he finally replies.
Another day, he tells Hikaru that where they are was once the farthest north. Beyond the fort's gates nearby was wilderness and barbarians. To be exiled this far was like death.
There was nothing we feared more, Sai tells him. To be sent here, forced into the unknown….
Finally Sai's premonitions are strong enough to make Hikaru shake in the mornings. That evening, they don't return to the ferry, but keep playing by the flashlight. The second day's evening, the batteries give out. As a ghost, Sai has no need for light, and so Hikaru calls out his plays, and Sai directs Hikaru's hands over the goban with his voice. A little left, no a little more…. It's like blind go for Hikaru, and it's like watching an infant's steps for Sai, although the intent behind each move is nothing so young.
After dawn on the fourth day, Hikaru is moving through the euphoria of the release of Sai's fear. It's enough that after Sai fades, he manages to hold himself upright for a few minutes, watching the wind move the pines and feeling the silence.
His parents are furious. The doctors are bemused: one goes so far as to remark that he thought this sort of idiocy was limited to computer game addicts in Korea. But despite the ache of the past few days, despite the tear-tracks still on his face from his few-days coma, Hikaru feels somehow calm, and maybe cautiously happy. He knows that if missing is possible in the wherever to where Sai has gone, he will be missed. And in return, he'll pay that coin from this world.
But that's okay.
But every action changed leaves effects. And in this better world of these two, Hikaru will never reach the potential he might have had in the game of go. He keeps the love of the game, but not the guilt. His opponents will notice a mysterious smile on his face from across the board, where he becomes a little lost in a memory that hurts just a little. But where he would have desperately sought a Sai he could only find in the ever-evolving position of the stones, here he'll just have nostalgia. Sai will be found in memories rather than in the improvement of his go.
This ripples outward. Although Hikaru will be quite good, he will lag, and Akira will not quite reach the same heights without him. There will still be a surge in youth popularity in go, but the international matches will still go to Korea and China often as not. The world of Japanese go will not shine as bright as it might have, could have been.
There are other effects, more subtle. A hundred years hence, machine intelligence is not as advanced, for one example.
Knowing even this, though, Sai would wish the same. If you got one wish in the other world.
For, you know. It was in coming to value Hikaru more than go that Sai did lose his ties to this present world.
And Hikaru would also give over the benefit of go as a whole for this might-have-been life, for the memory of valuing and being valued, and of ghosts together over the sand, under the pines.
But his wish (if he got one wish) would have been (just) different.