Although The Lines that Define Me is about suiboku-ga, or traditional Japanese ink painting, that's really only the vehicle through which the characters express themselves. Aoyama, the protagonist, is clearly not doing well from the moment we meet him setting up for an art exhibit – he's worryingly lightheaded as he heads for the door and definitely on the thin side. That catches the eye of grandfatherly Kozan Shinoda, a renowned ink painter, and he immediately takes the young man under his wing, feeding him and then taking him around the exhibit. At the end, he invites Aoyama to come study under him, and there's a sense that this is not just because Aoyama clearly has an eye for ink painting; there's something very, very wrong in Aoyama's life, and Shinoda clearly wants to help him.

Of course, Aoyama doesn't have any idea who this man is, and his hesitancy to trust him fights with his reluctance to say no to an elder. At some point, someone clearly taught Aoyama manners, and there's a sense that he holds onto that as one of his few guiding influences in life. Even before we learn about what's going on with him there's a sense that he's adrift, and by the time we see where he lives even someone less astute than Shinoda knows that Aoyama's in a difficult, if not outright bad, place. Aoyama has a wonderful eye for ink painting, but that really just makes Shinoda's work easier, because even if he didn't there's a definite sense that the old man had no intention of just walking out of Aoyama's life after feeding him an expensive bento.

The hints are beautifully sown throughout the obvious plot about Aoyama learning this traditional art, which he does, in fact, have a talent for beyond just analysis. He lives in a large, empty apartment, with only a low table in the center; unpacked boxes speak to the fact that he has more belongings, while the fact that he hasn't bothered to unpack them tell us of his depression. His obsession with ink painting as he learns it reveals how many empty spaces there are in his life as well; he could fill them, but until he meets Shinoda, he seems to have no drive to. And finally, his comment to Chiaki, Shinoda's granddaughter, that he has money he doesn't know what to do with all point to depression stemming from a terrible experience, something backed up by the apartment and the fact that he mostly eats instant food because he doesn't appear to much care about what he puts in his stomach. That he decides to actually cook a meal after an early visit to Shinoda's house shows how just having a grandfatherly figure makes him want to try harder.

Chiaki and Shinoda's other apprentice do eventually notice his depression – as well as the fact that Aoyama plainly isn't eating enough – but the old man saw it right from the start. He's been trying to help Aoyama learn to cope by stressing the meditational aspects of ink painting, but Aoyama is clearly still hurting. That makes his relationship with Chiaki an interesting one. The young woman is about his age, but she's got her own emotional burdens that make her a very prickly person, particularly where Aoyama is concerned. She's aghast that her grandfather has taken in a rank amateur as an apprentice, especially since she feels that he doesn't devote enough time to teaching her, his actual granddaughter. She comes off as spoiled and a little selfish, but as she spends more time with Aoyama, she comes to recognize that he's hurting and in need of help. Thankfully for both the character and the story she doesn't immediately soften completely towards him, but she does slowly warm up as she realizes that while she's been painting for acclaim and prizes, he's painting for a very different reason: solace. The artwork, both in terms of the ink paintings and the general manga art, works well with this, capturing a delicate, ephemeral quality that speaks to what Aoyama is going through.

The art, therefore, is an allegory for Aoyama's life. There is beauty in sadness, but that's only if you don't overdo it and let it take over, and that's what Aoyama needs to learn. At one point, Shinoda tells him that, “The goal of this isn't to succeed. The goal is to give it a try.” That's not only good advice in general, but it's also what Aoyama desperately needs someone to tell him: that as long as he tries, he's doing enough. Since he's just barely existing before he meets Kunoda, trying is, for him, a major accomplishment, and ink painting becomes an allegory for him changing how he's been living. As allegories go, it's a good one, and even if you don't think art is your thing, I highly recommend picking this up, because like all good art, it's true meaning is in the eyes of the beholder.