Period 41: The Erasing Blackboard
Period 41
Volume 10
Previous Period 40: Midnight Kotatsu
Next Period 42: Best Friend Chocolate
The Erasing Blackboard is the 41st chapter of the Zekkyou Gakkyuu series and 2nd chapter in the volume 11 manga.


If you write on a specific blackboard in red chalk and erase it, the object will vanish as well. After Kaori decides to test this rumor out to see it is indeed true, she takes it upon herself to get rid of unpleasant things plaguing every day school life.

Yomi's IntroductionEdit

In the middle of winter Yomi walks through the school courtyard surrounded by other students. She asks the Reader if they are enjoying their co-curricular activities, but to those who answer no, there is a solution for that.


During break Kaori hangs around in class with her friends while sadly observing a group of boys playing basketball. She also has a relay for P.E. today, and a progress test in math- both of which she hates. The only thing to lift her spirits is watching one of the boys, Isaka, a cool schoolmate whom she has a huge crush on. She wishes they were closer; but she can only sadly watch from afar as Sari, a girl he's been friends with since kindergarten joins them. Kaori wishes she could enjoy her day more like they do.

It's then her friend suggests that they draw on the blackboard to pass the remainder of their free period and she agrees. As she draws with her friends Kaori writes about how much she hates math and disliking school because of how boring it is. She sees everyone else have fun but she can't bring herself to enjoy it.

At home, Kaori tiredly collapses and her sister asks about her mood. Kaori expresses surprise seeing her, and she explains coming home early because the school is holding its testing period. Seeing how happy her sister looks, Kaori continues to complain; which doesn't surprise her older sister. She mentions how frequent this is and teasingly brings up the "execution blackboard", one of the seven mysteries at her school. When Kaori expresses confusion she realizes it probably hasn't spread to her school yet and explains to her that on the second floor is an abandoned classroom. One must write whatever it is they wish to eliminate in red chalk, then erase it, then it will vanish. She doesn't really believe in it though, despite several boys claiming to have tested it out. Since then a teacher has come by and locked up the room so nobody can go inside.

The following day, Kaori curiously decides to test the rumor having nothing better to do. She locates the locked room and is about to leave until realizing she can crawl beneath the sliding portion of the door to get inside. She checks to make sure nobody is watching her before doing so, then she gets out her red piece of chalk while approaching the board. She writes Math Progress Tests and erases it. She sees no harm in trying this out, considering it's just a lie. 

During class, Kaori is surprised to find out the Progress Tests are being discontinued. Everyone is very happy, and during the next free period she returns to the blackboard, wondering if it actually worked. She decides to test it again by writing down Tomato's in the school lunch and erases it and once again, and upon her return she overhears someone remark that despite tomato being on the menu there is none in the food. One of her friends is very happy, along with Kaori as she realizes the blackboard rumor is true. What's even greater is that because of the teachers trying to dispel the rumor by locking up the room, she's the only one who knows about it.

It's then she hears Isaka, who points out to a friend how much he dislikes tomato as well. She is glad to know they share something in common, and it dons on her that she can use this blackboard to make others happy and quickly gets to work, starting with eliminating the relay in P.E. and the scary stray dog by the west gate that nobody likes. She is happy to see how much everyone is enjoying themselves as of late and continues to eliminate problems; like Kurohane, a bully they happen to find harassing a girl for her homework. She rids of bullying, and suddenly Kurohane has transformed into a kind and considerate girl who is doing her own homework now.

As she overhears Isaka and his friend discussing how good things have been, Kaori happily enjoys the attention she gets; even though nobody knows it's her doing. But this is short-lived when one of them suggests it must be Sari's doing; she must have spoken to Kurohane. When Sari arrives the group celebrate "her" success and she attempts to figure out what is going on while Kaori stares in displeasure. As Isaka and his friend speak about how great Sari is, she gets frustrated as Isaka's friend starts teasing them, implying Isaka has a crush on her.

During break, an enraged Kaori rushes back to the blackboard and prepares to write Sari, but she stops and appears horrified realizing what she almost did. She steps back and thinks about what brought her to this decision, realizing that she can't do such a thing; until she overhears them in the hallway a bit later and Sari asks Isaka about their relationship. His awkward silence and behavior only confirms her worst nightmare, and with no remorse she writes down Umezawa Sari, then erases it.

Once class resumes, everyone begins to worry as they notice Sari has gone missing. She was there earlier and they wonder if she might have left without telling anyone- but that isn't like her. Kaori remains silent and thinks about how much she really, really, really hates Sari. She's a horrible girl for enjoying the attention she gets from others, and because she believes that she deserves to stand by Isaka's side. But with Sari gone, she can get closer to him now.

Seeing how down Isaka appears to be, Kaori approaches him and offers to play basketball with him and his friends, as they are now missing a player. Isaka accepts but his friend tries turning Kaori away because she can barely play the game, but Isaka gently chastises his rudeness and suggests giving her a chance.

Once school ends, Isaka is preparing to go when he observes a nearby window of the other school and watches Kaori sneak inside. With suspicion he takes off.

The following day everyone is alarmed to hear that Yamaguchi has gone missing now. With two students missing everyone is starting to grow uneasy- but Kaori remains indifferent, being the only one to know what is actually going on. She is angered when she witnesses another girl begin to bully an innocent girl, who sadly asks for Sari to return to protect her. 

Kaori returns to the locked room, deciding that she isn't really doing anything wrong. She begins to wonder whose names she should write down today and recalls how disgusting it is to watch other girls suck-up to Isaka; who suddenly shows up before she can do anything and expresses incredible anger. He brings up that his older sister told him the rumor and initially he didn't believe it, but now he has proof and he has no choice but to tell someone. Alarmed and in a panic, Kaori quickly evades him and runs down a nearby hall.

Not only was she caught, but now he will never forgive her.

Sadly, she comes to the realization that she can't return to class either because he'll tell everyone else. Anyone who holds a grudge against her -like Isaka, or the girl being bullied- could try to erase her next. In tears Kaori looks around the corner to find him telling a nearby teacher, and hurriedly she runs past them and into the room, slamming the door shut and locking any possible entry ways. Both of them try to convince her to open the door but Kaori refuses, approaching the blackboard again. Before she risks being erased she will rid of them first- but upon realizing that the teacher was just on the phone before she ran in and called the police, she doesn't have long before the entire world finds out what she was doing.

Completely having a mental breakdown, Kaori writes everything but me on the board. She will be safe this way, and she steps back to admire her work before erasing it. No longer hearing Isaka or the Teacher, Kaori calms down and turns to leave; but in doing so she finds herself entirely surrounded by white.

As this is going on Isaka and the teacher have finally got the door open. But to their shock, they can't find Kaori anywhere; only the chalk and eraser laying on the board.

Yomi's EpilogueEdit

Yomi observes Kaori as she tries to find someone or something within this void she's brought herself to, and she remarks that many people want the comfort of things they are content with, as well as something they want gone. If they have such a blackboard it is possible. She begins to draw on the board, saying that everyone must also be responsible.





Period 1: The Devil's GamePeriod 2: The Bonds Of A CursePeriod 3: Mary's Dining TablePeriod 4: The Abandoned School At MidnightPeriod 5: Bloody ValentinePeriod 6: Graduate Number 108Period 7: Supplements For The BrainPeriod 8: The Matching ClassPeriod 9: Kasako-San is ComingPeriod 10: The Truth About Yomi - Part 1Period 11: The Truth About Yomi - Part 2Period 12: The Endless Game of TagPeriod 13: Shii-Chan's DiaryPeriod 14: From The Land Of MirrorsPeriod 15: Execution ClassroomPeriod 16: The Girl Under The BedExtra Class: Black Cat SayaPeriod 17: Black ForumPeriod 18: Miracle BallPeriod 19: The Money TreePeriod 20: Best FriendPeriod 21: The Slit Mouthed WomanPeriod 22: The Land Of MermaidsPeriod 23: The Day I Became A Demon - Part 1Period 24: The Day I Became A Demon - Part 2Period 25: Friendly Apartment ComplexPeriod 26: Scarecrow TeacherPeriod 27: Make-Believe SistersPeriod 28: The Do-Gooders ClubPeriod 29: The Requirements Of A BellePeriod 30: Last White DayPeriod 31: My Older Brother And IPeriod 32: The Queen's TrickPeriod 33: The Toilet GoddessPeriod 34: Hell's Clock - Part 1Period 35: Hell's Clock - Part 2Period 36: The Fish FamilyPeriod 37: The Witch of the Library RoomPeriod 38: Soprano of MiraclePeriod 39: At Emily-chan's HomePeriod 40: Midnight KotatsuPeriod 41: The Erasing BlackboardPeriod 42: Best Friend ChocolatePeriod 43: Marionette's LoverPeriod 44: Ding Dong LadyPeriod 45: Mei-chan's TextPeriod 46: Yomi-sama's Facts -Prequel-Period 47: Yomi-sama's Facts -Sequel-Period 48: The Sea of SilencePeriod 49: Beautiful Mother & DaughterPeriod 50: Friend Of The Science RoomPeriod 51: The Cleaning ManPeriod 52: Ghost Channel
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