What is CTF (Capture The Flag)?
CTF, or Capture The Flag, is a cybersecurity competition where participants aim to find hidden strings known as “flags,” which serve as the correct answers to various challenges. Competitors use a wide range of cybersecurity skills—such as network analysis, programming, and vulnerability assessment—to solve problems. A “flag” is a metaphor for confidential information and can take many forms, including encrypted strings or specific files located on competition servers.
CTF is more than just a technical contest—it provides an invaluable learning experience where participants can develop practical security skills, enhance creativity, and strengthen logical thinking. In recent years, CTF events have been hosted by universities, companies, and conferences around the world, playing a vital role in training the next generation of cybersecurity professionals.
Competition Formats
CTF competitions generally fall into two main categories:
•Jeopardy-style — A problem-solving format that emphasizes speed and accuracy.
•Attack & Defense — A real-time, team-based format focused on both offense and defense.
Jeopardy-Style
This format consists of multiple small challenges from various categories, allowing participants to choose and solve problems of interest.
Challenges range in difficulty and typically cover topics such as cryptography, web security, reverse engineering, binary exploitation, and forensics.
When a participant successfully solves a problem and submits the correct flag, they earn points corresponding to that challenge.
Attack & Defense
As the name suggests, this is a real-time, team-based competition where both attack and defense take place simultaneously.
Each team receives an identical server environment containing vulnerabilities. The objective is to exploit other teams’ servers to capture their flags while simultaneously patching vulnerabilities to defend one’s own system.
Victory goes to the team that captures the most flags and best protects its own infrastructure.
Because success depends on swift and strategic coordination, teamwork, decision-making, and effective management are essential.
Features of ICC Tokyo 2025
ICC Tokyo 2025 brings together exceptional young talents under the age of 26 from around the world. These top competitors, selected from their respective regions, will form international teams and compete at the highest level of cybersecurity excellence.
On Day 1, participants will tackle challenges in the Jeopardy-style format, while Day 2 features the intense Attack & Defense format. This dual-structure competition tests not only individual technical expertise but also teamwork, strategy, and adaptability across different cybersecurity domains.
One of the defining features of ICC Tokyo 2025 is its inclusion of the Attack & Defense format—a rarity even among global CTF competitions. This unique structure makes ICC Tokyo a standout event on the international cybersecurity stage.
All challenges and competition infrastructure are developed and managed by Japan’s top-tier CTF players. Drawing on their extensive experience and deep expertise, they ensure that ICC Tokyo 2025 delivers high-quality, fair, and intellectually stimulating challenges for all participants.
Making Cybersecurity Competitions Visible
ICC Tokyo 2025 aims to transform cybersecurity competitions—typically invisible to the public—into an intuitive, enjoyable experience for everyone. To let attendees feel the intensity and strategic maneuvers of the competition, we're evolving our visualization methods by incorporating Japanese pop culture.
Connecting Technology and Culture Through Expression
Cybersecurity competitions are complex and difficult to understand without background knowledge or expertise. Therefore, for competition visualization, we adopted a “cyber pop” visual approach that blends Japanese pop culture elements like games, anime, and manga with the cyber space.
Set in a virtual space incorporating Japanese motifs, we express scoring and offensive/defensive developments through character movements and background changes. This allows even visitors unfamiliar with CTF rules to intuitively enjoy the flow of the competition.
Visualizing the Competition Through Characters and the Virtual World
The avatars/characters navigating the virtual space feature a fundamentally androgynous and approachable design. Design considerations ensure they are distinguishable not only by color but also by shape.
The eight characters combine “cuteness” and “coolness,” designed to create a positive impression that excites everyone.
-
KIRIN
AFRICA -
TIGER
ASEAN -
DRAGON
ASIA -
TANUKI
CANADA -
FOX
EUROPE -
SHISHI
LAC -
DOG
OCEANIA -
RABBIT
USA
This charming character dashes through cyberspace, clearly illustrating the game's offensive and defensive maneuvers.
Solve problems to earn flags, and color spreads across the virtual spherical stage.
Progress in the competition is visualized like a territory-capture game.
Set on each team's server, cyber battles unfold through character movements and light effects.
Spectators intuitively grasp shifts in the battle's momentum.
