For No1 otaku
Platform Company

We are Arithmetic Inc. team

For Gateway

Striving to be the
world's No.1 'Otaku' Marketing Company
We are one of the biggest company for woman romance game in the world

Our strategy is simple.
We bring the Japanese 'Otaku' culture as our business domain within and outside Japan.
Standardization of services with increased leverage makes us possible to provide various services and acts as content providor's infrastructure to create gateway

Strong Points


overseas line

We provide dating simulation games for women which are enjoyed by 6 million users worldwide. Since our company owns the structure of deployment, we are fully equipped to release contents to English-speaking countries・Asia・Europe with possession of massive data of each region as well as deployment know-how.


arismile game engine

We provide in-house produced software and third-party softwares. Simulation game engine that allows multi-platform deployment called "Arismile" is provided as content-type platform.

→→Free specifications of arismile
◆this game engine system really fits for Japan,but we this except Japan,another system is much better.So we open new engine in September this year.

domestic line

Domestically our dating games are enjoyed by several million users. Knowledge and marketing activities are fully utilized to accurately release hot contents. This accurate monetization system to women's line-up optimizes the entry to other businesses and it's monetization structure. It is our next step by utilize the stocks of software know-how.

What's New?

Our website has been renewed.


OUR PROJECTSFor making new markets for world

  • Portfolio Item

    Social Series

    These are dating-simulation series with story, avatar, and many events. This series holds the most users in our company's products from all across the world.

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    Love Diaries

    This series is distributed as SP series. You can play up to the prologue for free, and purchase the contents after that. This is content supported on iOS and Android.

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    Unlike the SP series, you can only read limited amount per day, but can read entire scenario for free. This content is supported on iOS and Android.

  • Portfolio Item

    OTACCO Media Project

    This is a curation service about otaku information in Japan. Currently available in Japanese, English, and French. Supported on smartphones and PC.

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    C TO C Platform Project

    This is contents-distributing platform targeted towards creators in the world. It is our mission to be world's number 1 marketing platform with significance.

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    B TO B Game Engine Project

    This is our corporative, "share-model" project. We distribute the game system used for our SOCIAL SERIES, LOVE DIARY SERIES, and ROMANCE SERIES free of charge.

Arithmetic Board Members

  • Team Member

    Chief Executive Officer
    Yoshitaka Terashima

    Born in 1979. After studying marketing at Boston University and graduating from faculty of commerce in Waseda University, experienced working as an national client's account planner at the advertising company Tokyu Agency Inc. Later on established the sales team as a Chief Executive Officer of mobile content company, and on 2007 established a consultation-type advertising agency and achieved great increase of sales of over ten million JPY alone. Established Arithmetic Inc. with the capital in 2008. Gained 12 kilos and lost 12 kilos within 5 years on his own. Owns 2 dogs.

    Team Member

    Chief Technical Officer
    Naohiro Morisato

    Starting from 1999 experienced through HPSD of Hitachi HP, Accenture and IBM until establishment of Plustar CO. LTD in 2006. Analyzed the attributes of reference website in real-time, and developed a system that allows full segment broadcasting based on POS data. Complained by the representative of the leading media corporation that the incredible efficiency of it makes the value of other media to decline, thus set back before achieving his ambition. Took part as a CTO of the company for 15 years. His hobby is to analyse correlated data of with his 10 Linux server running with 2Gbps at home.

    Team Member

    Chief Business Officer
    Asuka Nishimura

    Born in 1983. Graduated from faculty of letters in Ferris University. After achieving the top performance as a sales of advertising department in IT venture company, transferred to CYBIRD CO. LTD to be engaged in negotiations with telecommunication carriers. Participated in establishment of game business at Arithmetic Inc. in 2009. After producing the first free BL game on mobile, she was engaged in production of grow games, until appointed as a manager of this company in 2010. From 2011 engaged in managing content business as a managing officer, and appointed as Chief Business Officer in 2015. Recently gave birth to a child, and currently working as a officer mom.

Pick up our contents

AppStore google play store logo

informaiton about arithmetic


Company name: Arithmetic Inc.

"Established: December 22, 2008
Representative: Chief Executive Officer
- Yoshitaka Terashima
Capital: 50,000,000JPY (100% owned capital)
Number of employees: 56 (including contract staffs)"


"2/F Hiroo Complex, 5-7-35 Hiroo,
Shibuya-ku, Tokyo 150-0012"


For consultation / inquiries regarding business, please contact by e-mail.