These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Accidental Innuendo: If you disregard (or, like Momo, don't know) that Hisa was going to challenge Yumi to a mahjong game, this exchange comes off as it.
Yumi: We got along well last night.
Momo: Last night!? Got along well...!?
Hisa: Let's do it again today.
Interestingly enough, in the manga, while Hisa seems to be intentionally giving Momo that impression, in the Zenkoku-hen version, where only Yumi is telling Momo what happened, it seems to be a combination of less-than-optimal word choice by Yumi and Momo's overactive imagination.
Saki is either an optimistic young girl doing her best to reconcile with her sister or an unstoppable demon who gleefully destroys the dreams of other young girls just so she can get back at Teru. To be fair in this game there's always loser and winner, and Saki is determined to win all the way to final when she saw Shiraitodai is in different block.
Teru's saying that she has no sister is typically seen as a cruel act that is proof that she's a Jerk Ass who is not the sister Saki remembers. But implications at a tragedy in the Miyanaga family's past suggest that Teru might have been emotionally affected in some way, and their estrangement may not be due to her hating Saki. A drama CD, admittedly one published before the anime was released, seems to indicate that the happy memory Saki had of Teru talking to her about what her name means happened while their parents were in the process of separating, and might have been intended as parting words of some sort.
Is Hiroe a Jerk Ass who's full of herself, or is her taunting of her opponents an attempt to get them to play at their full potential for her maximum enjoyment? Hisa, who started her match with Hiroe in a Heroic BSOD, seems to lean toward the latter, and you can also see that Hiroe is, outside of matches, fairly nice to her little sister and the rest of her teammates.
Is Coach Kubo of Kazekoshi a tough, but fair mahjong coach, or does she excessively punish her players for minor mistakes? Additionally, has she been like this all along, or is this in response to Kazekoshi losing to Ryuumonbuchi in the prefecturals last year, which caused her to believe that Kazekoshi had become complacent and needs to take their games more seriously?
Arc Stall: The series has spent a long time in the semifinals; as of this writing, it's taken almost two dozen chapters to get through the first three matches of the semifinals. Part of it is because the chapters don't cover much ground, and part of it is because they don't come out entirely regularly.
Myth Stall: Saki is still a long way from reconciling with Teru again, especially considering that she seems unwilling to even talk with her, believing that it will be no different than the last time they spoke. More recent chapters have indicated that there's more to the rift between Saki and Teru than just mahjong, with a montage of images in Chapter 102 and 104, and Nishida saying she found a lead in Chapter 128, but the narrative quickly shifts back to the tournament.
Teru, with the main point of contention being her refusal to speak to Saki or acknowledge their being related. Some still like and/or sympathize with her, but others don't think anything justifies her treatment of Saki.
Saki and Nodoka fall into this. Some see them as boring while others are more favorable to them, especially those who ship them together.
Counterpart Comparison: The series is often compared with Girls und Panzer, in that the main character, who hates the game their family plays because of their attitudestowardwinning, ends up being a key player in her new school's efforts to win the championship, and rediscovers her love of the game in the process. Several parallels are drawn between characters, such as Teru and Maho, although in their case, while Teru has denied having a sister, Maho not only has not done so, but bears the responsibility of being Nishizumi heiress so that Miho will be free to live and do tankery her own way.
Despite having only two appearances in both the Anime & Manga, with only an onomatopoeia to her credit in terms of dialogue so far, Awai became so ridiculously popular with the fanbase that she actually gained a berth in Sai Moe 2010.
Kamigaki was only in the pre-prefecture round and, to be fair, had none of Awai's design that warrant anything, and frankly was not that popular with Western fans, but she did manage to get into Sai Moe 2009.
Touka: I'm going to lick you over and over and savor this delectable flavor!
The above quote was said as the voiceover to her spearwoman mahjong avatar molesting Nodocchi and Touka licking her lips. Even though she probably has no actual romantic or sexual interest in Nodoka, that scene is pretty heavy in the implication.
Awai and Himeko. She was very amazed that Himeko was able to surpass her innate ability. (She also said that she was "turned on" by Himeko's ability in the original Japanese context.
Despite wishing to topple her team, Toyone is a HUGE fan of Jindai, to the point at which Kurumi has to remind her that Jindai is the enemy. She's also shown interest in Nodoka, as another "mahjong idol".
While Momo only has eyes for Yumi, she coins the nickname "Boobs-san" for Nodoka, and after she gets over her initial shock at Nodoka being able to see her discards, she thinks it might end up being a fun game.
Hisa finding Mihoko's right eye pretty and Mihoko wanting to see and play against Hisa again went back to when they were opponents in the middle school individual tournament.
"Funny Aneurysm" Moment: Yuki's accusing Nodoka of hiding tiles in her breasts becomes somewhat less funny when you get up to the prefecturals and hear Hajime's backstory- she did, in fact, cheat in a game of mahjong in the past (through sleight of hand), and feels guilty about doing it.
Incest Yay Shipping: Saki and Teru, which often ignores or reinterprets Teru giving Saki the cold shoulder, as well as claiming that she doesn't have a sister, which some people interpret as wanting Saki as a lover rather than a sister.
There are also jokes that the series is set in an alternate universe where not only is mahjong extremely popular, but also panties were never invented.
Memetic Sex Goddess: In fandom, Hisa is universally regarded as a Pimp who can win the affections of her opponents with relative ease, given her stunningly good looks and incredibly charming demeanor, based off her Les Yay moments with Mako, Mihoko, Yumi, and Haru. Even NODOKA has had a moment with her.
Offscreen Moment of Awesome - In the Nationals, Mako completely wiping the floor with her opponents in her Quarter-Final match is skipped after The Glasses Come Off. This is largely averted in the anime, which shows the match in more detail, although it's wrapped up in about half an episode.
Ron the Death Eater: Some fans like portraying Teru as far more cruel to Saki, as well as emotionally unstable.
Rooting for the Empire: A noticeable portion of fans root for Kiyosumi's opponents in the tournament, especially Tsuruga, which, like Kiyosumi, is also an underdog in-universe and also has a great deal of Les Yay between Yumi and Momo.
The Scrappy: Teru has quite a few haters in the wake of her declaring that she has no sister, signifying that she's essentially disowned Saki; while Saki still wants to reconcile with Teru, many fans instead want to see Teru get her comeuppance.
The Usuzan team is getting a fair amount of hate over poorly their first three players are doing. By the end of the third round, they only win once and have a score that is presumably in the four digits, putting them at risk of not only going under and getting eliminated, but also bringing Kiyosumi down with them, since Kiyosumi is in third place.
Saki qualifies, given how frail and delicate she is. She really shines, however, in any scene regarding her older sister (Or whenever she gets lost.)
Momo is in this ballpark as well. She's gotten so used to being ignored that she's invisible because of it, but all she wants is one person to notice her. D'awww...
Kuro. Really, one can't help but pity the poor girl, especially when she's reduced to a whimpering and sobbing mess in her match against Teru. Her tendency to hold onto her dora tiles like her Missing Mom once suggested also indicates just how much her mother's passing affected her.
Koromo too. While at first she may seem like nothing more than a villainous mahjong demon, she masks what she truly feels with her own arrogance and ego, though in reality, either way you look at it, she's just fragile young girl looking to make friends, end her loneliness and cope after her parent's death. Awww.