Doubly disambiguated

After Iori claimed her spoils of victory from Sherbert, she immediately challenged Sandy while Mimoko challenged Sherbert.

"Guess you're going for me now. Well rules are chill, all you gotta do is play black on rapid time. Now let's surf," Sandy smiled as she opened the game by moving her pawn to f4.

"Guess your elo wasn't a joke, you suck ass," Iori snickered as she moved her pawn to d5.

"Oh? This coming from someone like you? I'm just playing things my way. In fact, consider this my middle finger to you. 850's a respectable rating," Sandy glared as she moved her king to f2.

"Wow, a birdy bongcloud. Guess we'll call this the Dutch BB opening," Iori snickered as she moved her pawn to d4.

"Hmm, that isn't in the move database... Guess we'll write it down," Daria shrugged.

"Okaa-chan... Ugh, I guess it's better than just classifying it as just a Bird's opening: Dutch variation," Mimoko sighed as Sandy moved her pawn to e4.

"Lol, you sure you're actually 850, cuz you're playing like you're 150. En passant check!" Iori shouted as she performed en passant and captured the pawn at e4 with her d-pawn, putting the king in check.

Rather than capture the pawn with her king, Sandy retreated it to f3.

"Capturing with the king actually was the best move. I guess she's playing worse against Iori-chan than she did against me," Mimoko thought as Iori moved her pawn to e2.

"I'm not taking that pawn. It's obviously a trap," Sandy scowled as she moved her pawn to g4.

"Uh... OK," Iori shrugged as she captured the queen at d1 with her e-pawn and under-promoted it to a knight.

"Huh? Why'd you promote to a knight? Are you mocking me?" Sandy glared as she moved her pawn to h4.

"Oh you'll see," Iori snickered as she moved her knight to d7.

Mimoko scowled as she glanced over at the board. "She's clearly planning something. Knowing her, it's probably something stylish," she thought as Sandy moved her knight to e2.

"Heh, she's moving like an idiot, or maybe she just wants to get out of here quickly. Well, if she does, she'll be leaving a broken woman," Iori maliciously thought as she moved her knight to h6.

Mimoko wrapped up her game with Sherbert and turned to focus on Iori's game. Sandy had just moved her king to g2 while Iori had moved her knight to f6. "That position... No, she couldn't be," she thought as Sandy moved her knight to g3.

Iori took notice of Mimoko's facial expression and winked while moving her pawn to e6.

"She had a guaranteed mate, but not anymore. Nonetheless, she'll still probably win. That poor girl's probably going to be shaken, but she has no one to blame but herself for getting in that awful position... And she just went back into mate... And Iori-chan just moved out of it," Mimoko thought as Sandy moved her king to h2 followed by Iori moving her knight to f2.

Sandy however, quickly blundered back into mate after moving her rook to g1, but Iori once again blundered out of it by moving her pawn to e5.

"I don't understand what you're doing, but it certainly isn't winning. I guess I'll just run down your clock," Sandy scoffed as she moved her bishop to g2.

"You trying to stalemate?" Iori asked.

"Well yes-"

"Guess you forgot about all the pieces on the queen-side. Now have any idea what the rarest move in chess is?"

Sandy stared in confusion, but since Iori's clock was ticking down, she decided to engage in conversation. "No, is it a castling checkmate or en passant checkmate?"

"Nope. Ever hear of a doubly disambiguated mate?"

"Doubly what?"

"Doubly disambiguated. It's when you have to give the exact coordinate of the piece you're moving, for example, Qe4f5."

"And?"

"I saw this video that said doubly disambiguated bishop mates have only happened once, while doubly disambiguated bishop capture mates and doubly disambiguated knight capture mates had never happened in a recorded game. Then as a result of the video, two games were played that featured a doubly disambiguated bishop capture mate, but only one featuring a knight one. Get what I'm saying?"

"No, I-"

"You about to be doubly disambiguated knight capture mated! Checkmate!" Iori manically shouted as she captured the pawn on g4 with the knight on f6, winning the game.

Sandy went pale with shock as she stared at the board. "...Huh? I... I lost to this... The rarest move ever... That's... Huh? Wh- Why am I crying?" she trembled as tears began to pour out of her eyes.

"Cuz you just proved yourself a fool, fool!" Iori snickered as she flipped Sandy off.

"Whelp, guess I know what new achievement badges we're adding next," Daria chuckled.

Once Sandy calmed down, she gave Iori the spoils of victory. "There, now can I leave? I'm not feeling well."

"Sure, get lost. We already beat you. In fact, I beat all of you, so it's maestro time- FUCK! I DON'T HAVE ENOUGH POINTS! NOOOOOO!"

"Oof, guess I lose the bet. Now I gotta shave my head again," Carol grinned.

Mimoko shot her and odd glare and demanded an explanation. Turns out, Carol had made a bet that Iori would beat Maestro Frisch first, but since Iori didn't have enough points while Mimoko did, she had lost the bet.

"This could still end in a draw though. Now, it seems you're the only two left," Mimoko stated as she stared at Mariano and Katie.

"Uh, like is there a reason you saved me for last? Because I hope it's not cuz you think I'm the culprit. In detective shows, the one that's focused on last is usually the criminal, so I don't want-"

"Then I'll play you next."

"Ey, you better not be implying that I'm the crook, cuz I ain't!" Mariano glared.

As soon as Sandy left, Iori snickered and pulled out the DESPER key case. "And the mystery is solved, now you can set forth any rules in rematches, yes?"

The full game:

White: SPCM Sandy Shores (850) Black: Iori Ishikiridokoro (1344)

1. f4 d5

2. Kf2 d4

3. e4 dxe3+

4. Kf3 e2

5. g4 exd1=N

6. h4 Nd7

7. Ne2 Nh6

8. Kg2 Nf6

9. Ng3 e6

10. Kh2 Nf2

11. Rg1 e5

12. Bg2 Nf6xg4#