Dear teams,

in the past weeks the Technical and the Executive Committee have done significant work on finalizing the rules for the Humanoid Soccer League rule book for RoboCup 2026. At the moment the last major point are being finalized. The first official draft of the rules is expected to be ready within the coming week and will be sent in a separate email.

The most up-to-date version will always be available at:

https://github.com/RoboCup-HumanoidSoccerLeague/HSL-Rules

**IMPORTANT**: This is a work-in-progress draft and will be subject to ongoing revisions.

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## Key Decisions Made

Based on recent Technical Committee meetings, here are the major decisions incorporated into this draft:

### Tournament Structure

Due to the number of teams, it is likely that a full round robin is not possible. As such, a Swiss - or similar - tournament structure will likely be adopted. Seeding to be discussed at a later date.

### Whistle Detection

Listening for the whistle will be included in the standard game of soccer:

- Teams will only be expected to listen to the whistle for the transition of the game state from "set" to "playing", for kick-offs, drop-ball, and penalty kicks.

- There will be a 10s delay for the "playing" signal from GameController.

### Communication Limits

Communication between the robots is event-based with a limited number of packages available to each team during a game (like in SPL). The packet limits are set to allow HL teams to transition to limited event-based communication.

- A team has a budget of 12.000 UDP messages per game. Each message should have maximum size of 512-byte. - Messages must be sent as UDP-broadcast and will be monitored by the GameController.

### Goal Dimensions at RoboCup 2026

Here are the decided dimensions of the goals to be used at RoboCup 2026. More details about allowable goal sizes are in the rules:

* S Division - Small Field: `1.8m x 1.2m` * M Division - Small Field: `2.4m x 1.6m` - Medium Field: `2.4m x 1.8m` * L Division - Medium Field: `2.4m x 1.8m` - Large Field: `3m x 2m` (Large field unlikely at RC2026)

**Note:** the goal sizes were chosen to allow for commercially available off-the-shelf goals to be used.

### Visual Referee (Former SPL)

The visual referee will not be included in this year's main competition rules. It may be moved to a new challenge for 2026 and added to the roadmap for possible main rules inclusion.

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## What's Next

This draft represents significant progress, but we expect further refinements based on team feedback and ongoing TC discussions. Please review the draft thoroughly and share your questions or concerns in #rule-book.

We'll continue providing updates from our TC meetings to keep you informed of any changes. There will be more frequent updates in the RoboCup Official Discord Major - Soccer #announcements channel, with periodic newsletters sent out for major updates.

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## Website

The new HSL Website is online:

https://hsl.robocup.org/

In the next weeks it will be populated with more information and turned into a hub of the league.

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## Important Reminders

* Registration Timeline: - Submission deadline: January 31st, 2026 (**TODAY**) - Team review period: February 3rd - 20th, 2026 - Announcement of qualified teams: March 2nd, 2026

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For questions regarding the rule book, please message #rule-book. For other inquiries, reach out via email or #ask-committees.

Thank you for your patience and collaboration as we finalize these details!

Best regards,

Heinrich Mellmann and Sam Griffiths

On behalf of the Humanoid Soccer League Technical Committee.