JST 09/11/2017 10:00 - 10/11/2017 16:00

CODE BLUE is an international security conference held in Tokyo.

This year CODE BLUE makes the first attempt to organize its own CTF, and binja takes on the role of its organizer.
In addition we engage TokyoWesterns as the co-organizer to make the CTF more interesting and challenging.

IRC: freenode #cbctf-2017


1st. 300,000 JPY

*Only for the top team


  1. This is a team competition.
  2. There is no limit to the number of people in one team. Of course you can participate alone though.
  3. The flag format is "CBCTF{something}", unless otherwise specified.
  4. You need to submit a flag to the score server in order to get a score.
  5. It is possible that one problem has multiple flags.
  6. A team that gets more score, ranks higher. If some teams get the same score, a team that made the last submission of a valid flag earlier, ranks higher among them.
  7. If you have a question, please contact us via IRC(IRC: freenode #cbctf-2017).
  8. For verification, the top team has to submit a writeup to get 300,000 JPY.


*If you take the following actions, you will be disqualified(and be forced out of the site if you are an on-site participant)

  1. To attack or disturb other teams
  2. To attack servers unrelated to problems
  3. To attack the infrastructure of the conference site
  4. To share flags or hints with other teams
  5. To try brute-force attacks to problem servers