Actor Allusion: One of the roles of Sumire Uesaka in this game is the Fubuki-class destroyer. Not exactly important at first glance, but remember that "Fubuki" is Japanese for "Blizzard". Which brings to mind the Red Baron moniker from another character she played: Nonna from Girls und Panzer.
Ascended Fanon: The anime adaptation takes some in-jokes from both the fandom at large and some of the spinoffs and canonizes them.
Akagi's Big Eater status comes front and center, after Fubuki witnesses the huge platter of katsu (or bauxite) curry she ordered. Kaga gets foisted with this as well come episode 6 (while her serving appears twice as large as Akagi's, it's likely that Akagi was halfway through her plate).
Inazuma's "nanodesu", despite not being used often in the game proper, turns into a proper Verbal Tic, used in all but one of her lines in Episode 2 and it gets over-killed in Episode 6 with about 17 instances of it — the most of out all Verbal Tic-using characters in the episode. And only second to Yuudachi's "Poi~" throughout the entirety of the anime.
Zekamashi, one of the fan nicknames for Shimakaze, gets used by Kongou in episode 4.note It comes from how her name is written on her gun cannons, with the hiragana going right to left as was common at the time.
Raiden, a fan nickname for Inazuma and Ikazuchi, also gets used, again care of Kongou in episode 6.
Nagato displaying a much less serious, far more cutesy and goofy side while in private, as shown in episode 8. Mutsu even teases her about it at the end of the episode.
After Haruna's second remodel had her with dazzle camouflage, some fans started joking that she wears striped panties. Cue official art confirming that yes, she does.
Iowa is frequently paired with Kongou in fan art due to their similar personalities. In the browser game, one of her hourly lines has her expressing admiration for the Kongou sisters.
Some fan artist have drawn Asashimo with shark-like teeth. Her Fall 2016 finally shows that she indeed has sharp teeth.
Many fan artists of both sides of the Pacific has drawn Kancolle-styled American Fleet Carrier girls as wielding guns instead of bows or scrolls. The first USN Carrier of this game, Saratoga, does end up wielding a gun to launch planes (an oversized Thompson SMG to be exact).
Originally intended to be a niche game catering mostly to the military otaku population with a modest budget and minimal advertisement, its popularity experienced a huge surge after its players (including, among others, KohtaHirano, whose Heroic B.S.O.D. on Twitter is most commonly cited as the main reason for the popularity surge) spread the word on Twitter and/or Pixiv.
Kisaragi's appearance in the anime and being sunk in episode 3 has resulted in loads of fan artwork of just her, when before she mostly showed up in group artwork or as a background character.
Development Hell: Kancolle Kai was originally scheduled to be released sometime in 2014. Then it was pushed back to spring 2015. Then to November 26, 2015. Then to February 18, 2016. To add insult to injury, the final delay was announced one month before the scheduled release. While it was finally released in February 2016, many fans fear that the repeated delays have hurt the game's chances. That worry turned out to be unnecessary, as the franchise's sheer popularity have made up for its shortcoming well enough to becoming one of the top-selling PS Vita game at its release.
Night-battles - Often used as a double entendre, and adopted because of the teasing way some shipgirls themselves use the term. Heavily popularized by Sendai, through her dialogue lines.
Displacement - Fanmade description for breasts; the greater displacement, the better. Though there have been some certain exceptions (some of the flat-chested carriers) and inversions for that matter (some big-chested Destroyers). "Fuel Tanks" are seen as an alternative term.
On the same note as Displacement, shipgirls' body parts are often referred by the ship's equivalent; bow for head or hair, stern for butts, rudder for legs, torpedo bulge for body fat, horsepower for musculature, etc.
Warship Girls is Chinese game for the Android with a similar premise like Kantai Collection. However, unlike Kantai Collection which features mostly WW2 IJN warships, Warship Girls features WW2 Warships from all sides of the War, and is also slated for an English release, which debuted at E3 2015. However, as of July 2016, due to bad blood between developer moeFantasy and distributor Patch Games, plans for an english version have been put on hold.
In the US, another Kantai clone is Victory Belles, an upcoming Free-to-Play rpg collection game & warship sim for the Web and iOS by American developer Black Chicken Studios. Victory Belles takes it Up to Eleven for not only having all WW2 Warships from all sides but having the ship characters voice by actual voice actresses from their respective countries (eg. British ships voiced by British voice actors and Russian ships voiced by Russian voice actors.), thus averting Fake Nationality.
Irony as She Is Cast: Sumire Uesaka is well known as a Russophile, yet the role of Verniy was given to Aya Suzaki. The official 4koma has Fubuki (whom Sumire Uesaka voices) communicating with the suddenly converted Verniy (Hibiki's second remodel) with (supposedly) good Russian, only to reveal that Verniy cannot really speak Russian apart from rudimentary words.
Played With in the official 4koma. One possible reason why Fubuki is able to speak fluent Russian (as mentioned in the Irony as She Is Cast above) is because a previous incarnation of Fubuki (a Harusame-class destroyer) was active during the Russo-Japanese War.
Amagi shares her name with the unfinished and ultimately scrapped battlecruiser Amagi, who was historically Akagi's sister ship. Some fanartists portray Akagi fawning over Amagi as a result of that, while in 4koma it goes with 'confusing linage' gagNote Unryuu-class girls are technically Hiryuu's children, and it was previously noted that Akagi and Hiryuu are cousins..
No Export for You: The only way to play the game is to register on the Japanese-language segment of the DMM website, which itself is inaccessible to non-Japanese IP addresses. This means to even register for the game, a prospective non-Japanese player will have to jump through a lot of hoops to do so (usually by using VPN), never mind getting to play the game, which then requires newly registered members to win a lottery for one of the limited slots per server. And competition is steep for server slots.
The January 29, 2014 update was a rude awakening for many foreign players, as the most prevalent method used to play the game (the API link) no longer worked, since DMM had the game purge its API lists every 90 minutes. This meant that anyone who wanted to play via API was now essentially playing on a timer, and they had to hop on VPN to renew their API link when the time was "up". The other choices were playing on the VPN full-time, which carried its own associated risk, mainly a chance of getting banned for using a single IP (as DMM would technically see a single IP used by multiple accounts), or purchasing a private VPN to play the game on. In any case, this caused a lot of grief for non-Japanese players, causing some of them to drop the game outright rather than face the hassle of renewing every hour and a half. However, said API renewal forced a lot of players to log in simultaneously, overloading DMM's log-in servers, and essentially making the game inaccessible to everyone for hours on end. It was quietly removed in a subsequent update.
However, API links is no longer a concern. A not-so-recent method involving cookie editing allows any foreign player to play the game properly.
Since Koreans hate this game, the anime series is not available on Koreanote Aniplus, a Korea-based TV channel, release Kancolle anime only in Singapore and Indonesia and not in their own country.. It isn't available in China, Taiwan, Hong Kong. Merchandise from this game isn't available in those countries, too.
However, in Singapore and other Southeast Asian countries, basically territories which suffered greatly under Imperial Japan, merchandise and Cosplays of the game's various ship girls are rather popular.
Permanent Placeholder: When the marriage system was first announced, it was called kekkon kakkokari (ケッコンカッコカリ), which means marriage (temporary) and implied that "marriage system" was just a placeholder name. Kekkon kakkokari would later go on to be the official name of the system on implementation.
Some fleet girls representing ships from the IJN, the Kriegsmarine, and the Regia Marina, that actually existed during World War II have yet to appear in the game. The most blatant case thereof would be that involving Shinano: Kadokawa had already released Alpha Art of her in supplementary materials ''way back in 2013'', but she has yet to make her appearance as of 2016. And with the successive debut of foreign Navies in the same year, (Three of them in fact, the latest being the Marine Nationale during the Fall event) the wait is expected to become longer. To add insult to injury, Warship Girls beat them to it, introducing its version of ''Shinano'' first.
To put into context the effect of the said trope on Shinano, Graf Zeppelin and Aquila (Both heavily unfinished carriers compared to the roughly-finished IJN supercarrier) were released in the Fall 2015 and Summer 2016 events, respectively, and were not even mentioned in early supplementary materials to boot.
When the Shoukaku sisters were given their second remodels, the developers promised they would be able to operate jet aircraft. To further the hype, the Ne Type Engine was released as part of the November 2015 ranking rewards. However, for over a year, there were no jets available. Considering the case with Shinano, to add even more insult to injury, Warship Girls introduced its first jet aircraft, the Yokosuka R2Y2, into the game in Summer of 2016. Jets finally made it into the game in December of 2016 with the introduction of the R2Y2 (Jet version of the Keiun), and Kikka.
Shrug of God: The developers are ridiculously closed-lipped about the origins of both the player-controlled fleet girls and their opponents, the Abyssal Fleet, which leads not only to fans making their own theories, but even to the official print spinoffs not agreeing on where they came from.
Sleeper Hit: The game was originally meant for the very niche market of military otaku, but thanks to some Colbert Bumps from big names in the manga and anime industries (the most notable example being Kohta Hirano's epic meltdowns about the game on Twitter) it got a lot more popular than intended.
The temporarily playable Fleet of Fog ships. Let's just say, if the marriage(temp) system, which was confirmed for eventual implementation before the Arpeggio event started (and was eventually implemented some time after it ended), with the concept for it being leaked out some time before that, had instead been implemented before the event started...