Tom: “Mary, when I return from this war, would you marry me?”
Mary: “Oh my God… Tom, what you’ve just said is shibou furagu (death flag)!”
Definition of “Death Flag” (死亡フラグ, Shibou Furagu)
死亡フラグ (しぼうふらぐ, shibou furagu) is a Japanese slang term that literarily means “death flag”. It describes a clichéd event or line in a story which suggests that someone is doomed to death in the near future. For instance, as written in the preface, if a man proposes to his partner before enlisting for military service amidst a devastating war, that is a typical “death flag” in a tragic play, suggesting that he will never see her again. Here is another example—imagine that a mysterious serial killing is taking place in a small isolated lodge, and people staying there are getting together to discuss how to protect themselves from the unknown murderer. Then all of a sudden, someone stands up and yells, “I don’t f*cking trust anyone here! I’m going back to my room, that’s way safer than being here.” — alas, he/she will most likely be found dead in his/her own room shortly, because that is a typical “death flag” in a clichéd mystery fiction.
“Death flag” is also used figuratively to indicate an event or line that foretells a catastrophic failure. For instance, when you are pulling an all-nighter to prepare for the exam tomorrow but struggling to stay awake, you might think, “let’s take a nap for 30 minutes to be more productive”, which, however, is a typical “death flag”— you will wake up in despair after the exam is over.
General Usage of フラグ (Furagu)
In Japanese slang, フラグ (furagu, “flag”) is used to indicate a variety of incidents that suggest what’s happening in the future. In particular, it often refers to “a romance flag”: a promising event or line which suggests that you will be in a relationship with someone. For example, if you coincidentally touch someone’s hand at a bookstore when two of you reach for the same book on a shelf simultaneously, that’s a typical “flag-on” moment in a drama or anime. If you notice that such “romance flag” has been turned on, you can say “フラグが立った”, meaning “A flag has stood”. On the other hand, if you inadvertently neglect such flag, that is “フラグを折（お）る”, meaning “snap a flag”. For instance, some of you may regret that you “snapped a flag” back in high school when you were too immature to notice your crush giving you an inkling of interest.
死亡フラグ consists of two words 死亡（しぼう, shibou）meaning “death” and フラグ (furagu) meaning “flag”. Here, フラグ is a loaned word from a flag in programming, which contains a binary value (true or false) and determines the next step of a program. Therefore, “death flag” means a watershed moment when someone or something are doomed to death or “deadly” failure.
This line is nothing but a “death flag” ( = This line totally suggests someone’s death or fiasco)
Two days before Christmas, she suddenly texted me and I thought it was フラグ (a “romance flag”), but it wasn’t at all.
(Note) Christmas is one of the most important days for couples in Japan.
Japanese Wasei-Eigo List (“Japlish”) and Their Meanings
Synonyms:虫の知らせ (premonition)、伏線 (foreshadowing)
Synonyms in English: premonition, a clichéd event or line that suggests someone’s death
Related words and phrases: 死亡 (death), フラグ (flag)