I'll be the first to admit that Gintama isn't the slashiest anime in the world. Hell, it's not even close to "romantic": Most of the in-show pairings are either one-sided (Sa-chan/Gintoki and Kondo/Tae), tragic (Hijikata/Mitsuba), casual (Katsura/Ikumatsu) or just plain "whut" (Yamazaki/Tama and Shinpachi/Pandemonium). I suppose this is understandable, since Gintama is first and foremost a comedy shōnen.
Still, it does have those more-than-friendly guy-and-guy moments. How else would you explain the fact that GinHiji (Gintoki x Hijikata) and GinZura (Gintoki x Katsura) are two of the most popular pairings in the fandom? Both of them have truckloads of "hints" throughout the series, though I'd argue that the most blatant ones are the following:
1st Moment - GinZura First In-Show Meeting: Will You Go (Out) With Me Again? (Episode 5)
I wrote "in-show" in the heading because of this one simple fact: Gintoki and Katsura "Zura" Kotarō are childhood friends. They grew up together, and fought together for the losing side of the Joui War, before Gintoki disappeared and Zura continued to harass the shogunate as a Jouishishi leader.
Apparently, it wasn't the last time either of them would see each other. Several years later, when Gintoki has his Yorozuya (along with big eater Yato girl Kagura and glasses-wearing teenage swordsman Shimura Shinpachi), he is asked to deliver a mysterious package by an equally mysterious man. When he does so, and the package explodes at its destination (an Amanto embassy), Gintoki gets implicated in a series of recent bombings. Naturally, he runs off with the rest of the Yorozuya, and bumps into a guy who upper-cuts him while screaming: "Zura ja nai, Katsura!"
Shortly afterwards, Zura hides out at the Yorozuya's place, introduces himself to Kagura and Shinpachi, and asks Gintoki to fight with him again as the legendary Shiroyasha ("White Demon"). Gintoki gives him a flat refusal, but not before bickering with Zura about his natural perm, which is so totally related to toppling the government. It got to the point where Shinpachi had to call them out for going off-topic: "What the hell are you two talking about?!"
What Fujoshis See: Even after years of not seeing each other, and barely having any contact at all, Gintoki and Zura still know how to push each other's buttons. If you listen to their bickering, it almost sounds like a conversation between exes: "Hey, what's up?" "I'm fine, you?" "Are you still free? If you are, well… How about we hit it up tonight and reminisce about old times?" "Like hell I'd do that."
2nd Moment - GinHiji First Meeting: I'm the (Former) Rebel and You're the Cop (Episode 5)
Interestingly enough, Gintama's two primary slash pairings kick off from the same episode. Not sure if it's intentional or not, but knowing how the peeps behind the show operate, it probably is.
Anyway, aside from Zura, we're also introduced to Hijikata Toushirou, the long-suffering vice-captain of the Shinsengumi. One of the Shinsengumi's tasks is to quell Jouishishi rebellions — which, of course, brings Hijikata into conflict with both Zura and Gintoki. Especially Gintoki.
Why Gintoki in particular? It's not like he's still affiliated with the Joui, right? I don't know either. What I do know is that their first meeting involves Hijikata thrusting his sword (ehem) into Gintoki's face (EHEM EHEM). This is followed by Gintoki making snide remarks about Hijikata's "swordplay", and Hijikata firing back about how he'll "eat up (Gintoki) like the salmon that he is." Gotta love the fukuchou's choice of words!
The two then battle it out using swords (of course), before getting coc- I mean, cut off by Sougo Okita, who fires a bazooka at both of them, not caring whether his fukuchou will bite the dust in the process. (Poor Hijikata, hahaha.)
What Fujoshis See: Considering that they just met, it's amazing how Hijikata and Gintoki play off each other from the get-go. They're basically each other's foils: black and white, straight-laced police and careless bum, mayonnaise and parfait. Also, when they talk about swordfighting — and actually do some swordfighting — it… can easily be taken to mean something else. I'll leave that to your fertile imaginations, folks!
3rd Moment - GinZura: If You Stay the Same, I Will Too (Episode 61)
Over the course of the series, we get multiple demonstrations of just how in-sync Gintoki and Zura are with each other. Of these, few can top the one from the well-liked Benizakura Arc.
The arc begins with a series of rōnin killings by a man wielding the Benizakura — a so-called "living sword" that becomes more powerful as it takes down more opponents. One of the man's "victims" was Zura himself, which results in a request by Elizabeth (Zura's giant pet duck-thing) for the Yorozuya to get to the bottom of the "murder".
Meanwhile, the Yorozuya gets another request: to find the Benizakura itself. Fortunately (or unfortunately) for Gintoki and the gang, the two requests are linked, and they find themselves in conflict with the Kiheitai, an extremist faction led by Takasugi Shinsuke, Gintoki and Zura's former comrade. Like Zura, Takasugi aims to topple the government, but is much more willing to do it by any means necessary — including the creation of a Benizakura-wielding army of samurai!
Raiding the Kiheitai's ship, the Yorozuya barely manage to hold off Takasugi's forces. That is, until help comes from an unexpected source. As it turns out, Zura is still alive! And what's more, he has quite the sexy new hairstyle, which Gintoki goes out of his way to comment on: "Did you get dumped or something?" To which Zura replies: "No, it's an image change. Did you get bombed or something?" Gintoki also says: "It's an image change."
After all that mutual joking, they fight off Takasugi's Amanto mercenaries the way they did during the Joui War. They also threaten Takasugi himself, while promising to each other that if one goes rogue, the other will cut him down.
What Fujoshis See: From the moment Zura's "murder case" lands on the Yorozuya's doorstep, until the two friends leap from Takasugi's ship a la Lupin, the GinZura feels are strong. For one, Gintoki attacks Nizou (Takasugi's henchman) right after the latter lecherously talks about how womanly Zura's hair is. For another, the way they bickered on the Kiheitai ship, after being ap for a while, makes you wonder why they don't just marry and grow old together already.
4th Moment - GinHiji: Two Is Better Than One, Indeed (Episode 166)
Remember what I said earlier about the BL moments in Gintama being "surprisingly subtle"? Okay, I take that back (for now) with this one. Seriously, you'd have to be really dense not to notice the blatant GinHiji fanservice in episode 166. (Not that I'm complaining.)
The episode starts off normally enough: Hijikata and Sougo are on a stakeout, and Sougo as usual isn't listening to a word his fukuchou says. So Hijikata ends up alone near a garbage dump, where Gintoki also happens to be. The two end up arguing about “who’s more pissed off”, which results in them getting handcuffed together. For some reason, Hijikata doesn't have the keys to his own handcuffs, so he calls Sougo over to free them both, and bring Gintoki to headquarters for obstruction of justice. But Sougo being Sougo, he chains them together with another pair of handcuffs instead!
What follows is one shippy/hilarious moment after another. There's dancing the tango complete with rose-in-mouth (pictured above), the increasingly ridiculous solutions to the almighty problem of "how are we supposed to PEE?", the eyebrow-raising shot of Gintoki wrapping his legs around Hijikata's waist while riding a bike, and another shot of Gintoki landing on top of Hijikata while staking out a Joui hideout.
Oh yeah, and there's the ending where Gintoki and Hijikata walk away from each other with similar exasperated expressions, complete with Takahashi Hitomi's "Wo Ai Ni" playing in the background. By the way, "wo ai ni" is Mandarin Chinese for "I love you".
What Fujoshis See: Did the animators just devote an entire episode to GinHiji? SQUEE!
5th Moment - GinHiji: We're Both (T)horny Bastards (Episode 247)
First off, a disclaimer: I ship GinHiji and GinZura equally. Just because there's more GinHiji on this list doesn't mean I see GinZura as a less valid pairing. Both of them have their merits, so please bear with me!
Anyway, let's get back on topic.
In the Baragaki ("Thorny") arc, we get to learn more about Hijikata. We learn that he's a bastard child of a rich guy, a younger half-brother to Tamegoro, and a "thorn" in most people's sides. This is why he warms up to Sasaki Tetsunosuke, a dim-witted young man who gets dumped on the Shinsengumi, because he couldn't get into the "elite" police force Mimawarigumi led by Sasaki Isaburo, his older brother.
Meanwhile, Gintoki gets arrested by Isaburo, and is assigned a mission to infiltrate the Joui gang called "Check It Out". Since Tetsunosuke was a former member of the gang, he gets captured by it, and is used as a hostage to stop the Mimawarigumi and Shinsengumi in their tracks. But Isaburo decides to disregard his younger brother's life, and have all the blame pinned on the Shinsengumi instead, so Hijikata responds by fighting.
In the process, Gintoki and Hijikata meet each other in battle, with Gintoki at one point declaring to Hijikata that he's the Shiroyasha. Once again, they display how well they fight together, and how they're both worthy of the name "Thorny".
At the end of the arc, we see Gintoki flying a paper airplane, followed by a shot of Hijikata in the hospital writing… and having a paper airplane fall by his bedside. Hmm, I wonder who Hijikata's plane came from?
What Fujoshis See: You know what they say about couples looking like each other over time? Well, judging by the image above, Gintoki and Hijikata are exactly that.
Also, the part where Gintoki admits that he's the Shiroyasha is pretty surprising, to say the least. For one, he's not the kind of guy who even hints at his past, so Hijikata being able to make him do that is… telling. For another, Gintoki may be lackadaisical and eccentric, but he's certainly not stupid. Why did he admit that he's one of the legendary Joui warriors to a member of the Shinsengumi, the Joui's enemies?
And that ending scene. Oh, that ending scene. If you think about it, there's no reason for Gintoki to communicate with Hijikata after the whole Mimawarigumi fiasco. He only got dragged into it, after all. Yet there he is, exchanging paper airplanes with a fellow "Thorny".
A Few More Words
I'm pretty sure there are a few more BL scenes in Gintama woth mentioning. There's basically every episode involving Gintoki and Hijikata, the infamous Katsura-fluffs-up-Gin-Sadaharu's-stomach scene, and even the crack arc where Gintoki drunkenly "does the deed" with Madao, of all people.
Now, I'm not suggesting that these moments should only be interpreted as romantic ones. The nice thing about Gintama is that you can view every scene the way you want, and still be "right", because the show's just too off-the-wall to have only one valid interpretation. If you see GinHiji/GinZura as ship mates, that's fine. If you see them as vitriolic best buds, that's fine too. At any rate, don't be afraid to sound off about Gintama's "ho yay" subtext in the comments section!