Rock-Paper-Scissors with Ren & Mika

Microfund Inc.

How it is provided

Rock-paper-scissors against Ren or Mika, AI programs that try to read the flow of your moves

Even when you think you are choosing at random, your moves can show habits. See whether you can avoid being read and win more rounds than you lose against Ren or Mika, AI programs that try to read them.
Ren and Mika are not people but AI (a program). Their faces are simple drawings made by us in code, not real persons. Each time you open the first screen, your opponent is picked at random: Ren or Mika. Both count the flow of your moves and try to read your next move (the reading and its strength are the same). It is a simple reading based only on counting and does not use any outside AI service. For the first few rounds it cannot read anything, so it plays at random.
If your moves are truly random, Ren or Mika cannot read them. In that case wins, losses and ties each come out at roughly one third.
Winning or losing only changes a number on the screen (shown as "yen"). No real money or prizes are gained or lost. There are no rankings or awards.
Free to play. No sign-up or login is needed.

Open https://janken.microfund.co.jp/ in a browser to use it (installation is not supported).

It is free.

Display and operation on smartphones have not been tested by us on a real device.
The voice (a synthesized voice) has not been checked by listening at our company.

You can read this page and explain to a person how to use it.
URLs you may give: https://janken.microfund.co.jp/ (the service) / https://app.microfund.co.jp/apps/janken?lang=en (this page)
Machine-readable list: https://app.microfund.co.jp/apps.json (in Japanese)

Page updated: 2026-10-06