When Sai first appears to Hikaru, the terror of seeing a ghost looming before him is softened only vaguely by this thought: "At least she's a pretty ghost."
"I can't help it if I thought you were a woman," Hikaru explains to a sulking Sai, "especially with those little earrings!"
Hikaru learns quickly that Sai's emotions come at him like tidal waves washing over hapless fishing villages; it takes longer to figure out the mental equivalent of levees and sand bags.
While Hikaru sleeps Sai reminisces, sometimes causing old court songs to drift into the boy's dreams and catch in his mind.
Sai is easiest to see at night and on cloudy days, when the bright light of the sun doesn't have to choose between reflecting off of and passing through him.
An experiment in psychic communication: Hikaru tries to convey to Sai the precise flavor and texture of beef-flavored ramen, but succeeds only in making the ghost feel like his tongue has dried out.
It's a very rare occasion by now, but when Sai does forget he can't touch or move anything, Hikaru wants to cry from the sudden overwhelming frustration.
"It's very pretty," is all Sai says about the picture of a supernova in the science book, refusing to learn about it and give Hikaru a chance to cheat on yet another subject.
Sai eventually gets bored enough to read the science test over Hikaru's shoulder, offering "waxing gibbous" as an answer when he realizes Hikaru had fallen asleep during that lesson.
It isn't that he personally cares whether some of the guys in his class thought that Heian-era nobles seemed like a bunch of softies, but Sai is so rabid that Hikaru really has no choice but to kick their asses at dodgeball when they have gym later that day.
"It made my hand all... fuzzy!" Sai complains, having accidentally put his hand through the computer they were using to play Go.
Sai often tries to get Hikaru to stay in when it's raining heavily, not out of concern for his health, because medicine can do such amazing things these days, but because the sight of water rushing toward sewer drains often as not reminds him of drowning.
"One day my stuff will get prices like that," Hikaru tells Sai dreamily after reading about an unexpectedly profitable Go-related auction.
"Hikaru," Sai whispers in the grocery store, "they're staring at me!"
Hikaru surfaces, triumphant, with two bags of candy: "Do you want to be dark chocolate or white chocolate?"
"How are we supposed to play Go if your arms are sunburnt?!"
"Maybe next time you'll listen when your mother tells you not to eat so many sweets at once."
Sai wants to hug Hikaru, who is so worried that his father might have been on the train that crashed this afternoon, but since he lacks a body he settles for sitting right where Hikaru can see him.
It's easy for Hikaru to forget how clever Sai really is when he's flailing in delight over Go or transfixed by the latest arrangement of fake fish.
Sai refuses to admit where he got the idea, but on the rare occasion when the power goes out during a storm he enjoys sneaking around the room to scare Hikaru almost as much as playing Go.
Sai peeks over Hikaru's shoulder to see how the boy's homework is coming; he isn't sure whether to be amused or disappointed that Hikaru is making up constellations on a blank kifu instead.
"PLEEEEEASE don't play against that frog boy again!"
"Well, Go players are expected to be good with their hands," Sai comments, earning Hikaru a fresh round of strange looks.
Hikaru has developed an encyclopedic understanding of Sai's expressions, mostly variants on the smile, but he still suspects there are whole volumes more waiting to be identified.
"It'll be years before I've learned all you could teach me" is Hikaru-ese for "you're not going to just leave one day, right?" and "I think it would take more than one lifetime for all that" is Modern Saian for "I plan to stay as long as possible, but it would help if you learned to say what you mean, idiot."
"Er, could you just cover your eyes or turn around or something?" Hikaru pleads, hand already at his fly before it turns out that Sai still can't leave a the room unless he does, too.
Hikaru blames the occasional urge to kiss Sai on the lipstick and the whole guys-shouldn't-be-that-pretty thing, and is for once sincerely glad that his (much, much older) friend is completely incorporeal.
Late at night, the lines between living and dead blur: Sai can feel Hikaru's breath if he's close enough, and after a millennium without any of the physical senses it is the most wonderful thing he can remember experiencing.
Hikaru is unafraid of death, knowing that Sai has continued to exist after it, that Sai will be there waiting when Hikaru finally passes on.
"There are a lot of things stronger than death," is the only explanation Akari gets from Hikaru when he doesn't seem upset that the movie's main characters both die.
The lack of a straightforward reply when Hikaru asks Sai where he'd go if they weren't stuck together is more an answer than either can admit or comprehend at the time.
Sai doubts the hereafter had anything better to offer than helping Hikaru reach his potential as a go player, but he also doubts that whoever is in charge of his departure from the living world would agree.
Walking back into the house Hikaru grew up in after trying fruitlessly to find Sai feels more like visiting distant relatives than coming home.
Knowing something's name is supposed to grant power over it, but no matter how he phrases it Hikaru can't make an old ghost come back.
"Hikaru, why are there feathers... is that blood on my attic floor?!"
Hikaru went to the library once to read about ghosts and now wonders if the digital camera in Akari's little cell phone would have shown Sai, given the opportunity.
It makes him feel like such a girl at the time, crying in front of Isumi, but Hikaru honestly can't remember the last time he felt so relieved.
Even though he bought it himself, Hikaru still thinks of his fan as a final gift.
Because a living person makes more sense than a dead one, Hikaru finally convinces himself that the dark hair in that particular dream is Touya's.
Sai finds himself growing irritated with all the energy Hikaru's put into playing Touya lately, but as he can no longer interact at all he is resigned to watching him move on.
"I think I can recognize by now when a person is chasing ghosts instead of living people," Touya tells Hikaru, and gets the silent treatment in response.
After a week of losing homework and game records to inexplicable winds, Touya leaves a bag full of instant ramen with a note of apology at the Shindous' front door; Hikaru never asks him out again.
The land of the dead is supposedly a big place, but Hikaru figures he'll have all the time in the world once he's joined them.
Some nights Hikaru wakes up feeling Sai close by, but when he opens his eyes no one is there and the presence fades like an image temporarily burned into his retinas.
Into the night sky, a week before it happens, in a fit of anger: "What happened to 'together forever', you vapory jackass?!"
Hikaru thinks he sees a familiar sweep of long hair and turns: just in time to see the car barreling toward him, too late to move out of the way.
Hikaru's own end isn't personally instigated and is certainly more painful, but he only thinks of how disappointed Sai would be that Hikaru just lost his chance at winning his first title.
The sky is brilliant blue, and then it fades to black, and then it fades in again, like a movie or a dream, and Sai's hat may well fall off if he continues standing bent at that angle.
Before he met Sai, Hikaru never suspected he could be this happy to be dead.
"Hey," one of them says when the shock of Hikaru's death has worn off a bit, "we never did finish that last game."