Sushi Kokuu Hen cover

Cover image for the series.

Sushi Kokuu Hen (Japanese: 寿司 虚空編)[1] is an educational Japanese webcomic about googology, drawn by Doom Kobayashi[2] (Japanese: 小林銅蟲). It has attracted considerable attention for its surreal atmosphere and "overwhelming incomprehensibility."

The comic began on September 11, 2013, and the first six episodes were published in the U-2 league of Shogakukan's Ura Sunday, which shut down at the end of 2014. It restarted on April 13, 2015, on Pixiv, where episode 7 was published with translations to English, Simplified Chinese and Traditional Chinese. Episode 7 of “Sushi Kokuu Hen” has the same content as episode 6 of another pixiv comic, “さいはて -Daydream Attractor-”.[3]

It was published on August 10, 2017 by Sansai books in Japan.[4]


Sushi Kokuu Hen ep7 p11

Page 11 from the English translation of episode 7, demonstrating the Ackermann function.

The story begins with the explanation of Graham's number. The title of the comic is "Sushi", and the readers expected to read story about sushi, but the first story was unexpectedly all about math.[5] As the story goes on, more advanced topics of googology, such as Fish numbers and chained arrow notation are presented.


Oyakata (boss) 
Boss of Sushi bar.
Sushi chef. His father disappeared when he was a child, and he lived with Oyakata since then.
Uruka Boufura 
Ghost of a daughter of Oyakata.
Oyakata mentioned only once in the first story, and detail is not known.
Creator of Fish number.
They operate the Sushi bar while Oyakata and Mashimo are absent.
Wrestler. His ring name is "Menka seihin Astral kimochi goran kudasai kamen" (Cotton-made Astral look at my heart mask)
Jinkaku ichiro 
Tonikaku man (Anyway man) 
Well, anyway!
Tonikaku lady (Anyway lady) 
Huh? anyway!
Last Boss police 
Police. Special guest invited from another cartoon.[6]

Googological concepts in each story

Series Concept
1st Graham's number, Arrow notation
2nd Fish number 1
3rd Fish number 1, S map, SS map
4th Googology, Tetration, Hyper operator, Ackermann function, Fast-growing hierarchy, Tritri
5th Chained arrow notation, Graham's number, Conway's Tetratri
6th Fast growing hierarchy
7th Ackermann function, Fast-growing hierarchy
8th Ackermann function
9th Fish number 2, Taro's multivariable Ackermann function
10th Fish numbers



  1. 寿司 虚空編 -Sushi Kokuu Hen- (pixiv comic) (English)
  2. Negineesan's Gwiki user page
  3. さいはて -Daydream Attractor- (pixiv comic)
  4. Publisher's site
  5. Why all about math! The webcomic "Sushi Kokuuhen" on Ura Sunday is too surreal. (in Japanese)
  6. ラスボス刑事 1話

See also

Googology in Asia

Fish numbers: Fish number 1 · Fish number 2 · Fish number 3 · Fish number 4 · Fish number 5 · Fish number 6 · Fish number 7
Mapping functions: S map · SS map · S(n) map · M(n) map · M(m,n) map
By Aeton: Okojo numbers · N-growing hierarchy
By BashicuHyudora: Pair sequence number · Bashicu matrix system
Indian counting system: Lakh · Crore · Uppala
Chinese, Japanese and Korean counting system: Wan · Yi · Zhao · Jing · Gai · Zi · Rang · Gou · Jian · Zheng · Zai · Ji · Gougasha · Asougi · Nayuta · Fukashigi · Muryoutaisuu
Buddhist text: Tallakshana · Dvajagravati · Mahakathana · Asankhyeya · Dvajagranisamani · Vahanaprajnapti · Inga · Kuruta · Sarvanikshepa · Agrasara · Uttaraparamanurajahpravesa · Avatamsaka Sutra · Nirabhilapya nirabhilapya parivarta
Other: Taro's multivariable Ackermann function · Sushi Kokuuhen