- Acceptable Professional Targets: A brief jab at Hayashida's salary as a teacher turns up in the same chapter as his first appearance; he correctly assumes that Rei's monthly salary and winnings as a professional shogi player is more than his, immediately irritating him when Rei doesn't deny it.
- Angel/Devil Shipping: Rei/Kyoko, with Rei being the Angel and Kyoko as the Devil. While there are fans of the work that don't want this to happen precisely because of this dynamic, there are also fans that are excited by the prospect of it once the romantic undertones of their relationship become more overt.
- Big-Lipped Alligator Moment: Episode 13's opening scene of Smith eating his breakfast. It's an odd scene with a stark contrast with the rest of the series in style and tone, with an jazzy track that's unlike the rest of the soundtrack and a runtime of two minutes. Unlike the scene in Episode 1 where Rei is silently walking to his match with his father, this scene tells the audience essentially nothing about Smith from his silence (other than he eats like a bachelor slob). In comparison, the original scene only took up a single panel and not nearly as much attention was drawn to his eating habits. Context for it can only be derived from an out-of-universe perspective; Shaft wanted to do a shot-by-shot homage of an opening scene from a drama.
- Base-Breaking Character: Kyoko. On one side, she is disliked by part of the fandom due to her treatment of Rei and her toxic behavior towards him; on the other, there are people who sympathize with her due to her tragic backstory and how the show fleshes her out, while avoiding making her a one-dimensional character whose only role in the series is to torment Rei. There is also a third camp regarding her (see Love to Hate).
- Broken Base: When news broke out that Studio Shaft would be doing the anime adaptation, forum threads and comment sections discussing the announcement had a wide variety reactions. There were those who gave positive responses, either out of love for Shaft itself or because they genuinely had faith they could do an adaptation of the series justice. Some approached the news with cautious optimism or trepidation. And lastly, there were those who were outright angered or dismayed, as if them picking the series up would result in some horrendous bukkake of every quirk that Shaft is (in)famous for. When the anime came out, this largely died down, though still a vocal minority of the manga's readers criticize Shaft's somewhat less subtle approach to the series.
- Jerkass Woobie: While Kyoko's actions by no means should be tolerated, it's not hard for readers to see why she turned out that way and sympathize with her.
- Love to Hate: Another way of feeling towards Kyoko. There are people who actually like her for how awful she is towards Rei, and who enjoy her bitchy side and the way she tries to make him fail in his shogi matches, to the point of finding her behaviour mesmerizing.
- Mind Game Ship: Another way of looking at Rei and Kyoko's relationship, with the latter being the manipulator.
- Moe: Almost all characters are prone to this perception, sure, but it's as if Momo's purpose as a character extends little past being the primary source of the manga's cuteness.
- Periphery Demographic: 3gatsu's target demographic is Seinen, but its soft art style and introspective look on life make it accessible to both genders and a wider age range.
- The Scrappy: An even bigger scrappy than Kyoko, who at least has redeeming points to her, is Hina's homeroom teacher during the bullying arc for being Adults Are Useless incarnate and for victim-blaming HINA for the bullying.
- Tough Act to Follow: Inverted these days; 3gatsu is far more popular and well-known than Chica Umino's previous manga Honey and Clover. However, before the anime was broadcast and had the series popularity boosted into mainstream, this was played very much straight: 3gatsu remained obscure for years compared to its predecessors, even as English translations for the series existed (albeit stagnant in its release schedule).
- The Woobie:
- Rei, due to his many personal problems the story reveals through its narrative.
- Starting from Volume 4, Hina becomes one as she starts falling victim to relentless bullying.
YMMV / March Comes in Like a Lion