• Don’t prevent other teams from having fun.
• Don’t share flags or hints, or you’ll be banned.
• Don’t attack (e.g. DoS) our infrastructure, or you’ll be banned.
• Don’t do automated scanning. It will be considered to be DoS.
• The flag format is TSGCTF{blahblah}, unless otherwise specified.
• The prize will be paid with PayPal. If it doesn't suit you, we can pay that in BitCoin at an arbitrary exchange rate we determine.
• The teams must publish the writeups of the solved problems in CTFTime to get their prizes.
• The number of members in a team is unlimited.
• People who belong to TSG are not allowed to participate in TSG CTF.

Support

If you have issue with TSG CTF, please contact us by joining official Discord server, and clicking "Create Ticket" button in the #ask-admin channel.

About “beginner” challenges

If you are unfamiliar with CTF, we highly recommend you to first take a look at the challenges with "beginner" tag. They will be released at the same time as the CTF launch.

In TSG CTF, Beginner's tasks are not "beginner-level challenges." We define a beginner's task as a challenge that does not require any experience or knowledge specific to CTF, but can be solved with knowledge that even a beginner has. Please don't be discouraged if you can't solve a "beginner's task". At times it can be hard!

About Final(en)

We are planning to hold an on-site final in Tokyo in Spring 2026 for the top-ranking domestic teams of TSG CTF 2025. Eligibility is limited to the top 10 Domestic teams (up to 4 members per team).

A Domestic Team refers to a team that meets both of the following conditions:

• All members participating in the qualifiers are residents of Japan.
• All members participating in the onsite finals are residents of Japan.

Notes on team composition for the finals:

• Teams aiming for the finals may still participate in the qualifiers with 5 or more members.
• The team members for the finals may differ from those in the qualifiers.

About Final(ja)

TSG CTF 2025では、成績上位のDomesticチームを対象に、 2026年春にオンサイト決勝を東京都内で開催する予定です。対象はDomesticチームの上位10チーム（1チーム最大4名）とする予定です。

Domesticチームとは以下の両方を満たすチームを指します：

• 予選に参加する構成メンバー全員が日本在住であること
• オンサイト決勝に参加するメンバー全員が日本在住であること

決勝チーム編成の補足として、

• 決勝に出場したい場合でも、予選は5人以上で参加していただいて大丈夫です
• 決勝と予選のメンバーが異なっていても問題ありません

Release Schedule

07:00 (UTC)

Genre	Difficulty	Author
pwn	beginner	@sashiming
rev	beginner	@mtmt
web	beginner	@aster-void
crypto	beginner	@alcea
crypto	beginner easy	@settyan117
crypto	beginner easy	@settyan117
misc	med	@dai
rev	med	@caphosra
pwn	hard	@iwashiira

09:00 (UTC)

Genre	Difficulty	Author
pwn	easy	@LLUUIIGGEE
pwn	med-hard	@iwashiira
rev	med-hard	@iwashiira
web	easy-med	@aster-void
crypto	hard	@JP3BGY
misc	med	@dai

11:00 (UTC)

Genre	Difficulty	Author
pwn	easy-med	@mikanami
crypto	easy	@jiei-univ
web	med	@iwashiira
misc	easy	@dai
misc	easy	@alcea

13:00 (UTC)

Genre	Difficulty	Author
misc	med	@iwashiira
misc	med	@dai

maybe

Genre	Difficulty	Author
web	med	@fabon-f
crypto	canceled	canceled