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Hnefatafl Board

Install

See how to install the software here.

Rules

See the rules here.

Artificial Intelligence

Learn about AI here.

Translate

If you want to add, update, or fix a translation, open an issue and state what you want to do. If it is a minor change, you can just update the code and submit a pull request.

Discord

Join discord here.

Help Me

If you have any issues with the software, open an issue on github.

Donate here.

Hnefatafl Org by David Lawrence Campbell is licensed under CC BY 4.0CC BY 4.0CC BY 4.0

Install

Login

Arch and Derivatives (Linux) @

In your terminal run:

sudo pacman --sync yay
yay --sync hnefatafl-copenhagen

Chocolatey (Windows)

Install Chocolatey.

Then install hnefatafl-copenhagen.

Debian and Derivatives (Linux)

Download hnefatafl.list to /etc/apt/sources.list.d/.

Then, Download packages.hnefatafl.org.asc to /etc/apt/keyrings/.

Then in your terminal run:

sudo apt update && sudo apt install hnefatafl-copenhagen

Flatpak (Linux)

See flathub.org.

F-Droid (Android)

  1. Go to Google. Scroll down to Enhanced Safe Browsing for your account. If it is on, turn it off.
  2. Go to F-Droid and download F-Droid.
  3. Open F-Droid, go to search, and install Termux: Terminal emulator with packages.
  4. Open Termux, then run the following:
# Only need to run this once per update.

pkg upgrade
termux-change-repo
pkg install rust git x11-repo
pkg install xfce termux-x11-nightly
git clone https://github.com/termux/termux-packages termux-packages-hnefatafl-copenhagen-dest
git clone -b hnefatafl-copenhagen https://github.com/robertkirkman/termux-packages termux-packages-hnefatafl-copenhagen-src
cp -r termux-packages-hnefatafl-copenhagen-src/x11-packages/hnefatafl-copenhagen/ termux-packages-hnefatafl-copenhagen-dest/x11-packages/
cd termux-packages-hnefatafl-copenhagen-dest
scripts/setup-termux.sh
./build-package.sh -I -f hnefatafl-copenhagen
cd output/
apt reinstall ./hnefatafl-copenhagen*.deb

# Repeat this every time you want to run the program.

export LIBGL_ALWAYS_SOFTWARE=1 DISPLAY=:0
termux-x11 -xstartup xfce4-session &
hnefatafl-client --ascii

Then go to Termux:X11 from the main menu. You may need to hold Termux:11 to go to the Preferences -> Output, then increase the Display scale %.

Redox @

Edit your user config to include:

[packages]
hnefatafl-copenhagen = "source"

You should be at least using the packages supplied via include = ["desktop.toml"]. Go to games and open Hnefatafl. After logging in and exiting the application, you’ll have to restart Redox, because the application is buggy.

There are also at least these bugs:

  1. There are no CJK fonts.
  2. On a button press two characters are read in instead of one.
  3. Backspace does not work.
  4. I think you have to restart Redox after entering the application, because TcpStream shutdown is not implemented.

Cargo (Linux, macOS, Windows) @

Dependencies (Linux)

ALSA development files are needed to build cpal on Linux (rodio dependency, hnefatafl-client dependency). These are provided as part of the alsa-lib package on Arch, libasound2-dev package on Debian and Ubuntu, and alsa-lib-devel on Fedora.

The package uses the mold linker. This is provided via the mold package on Arch, Debian, Ubuntu, and Fedora.

Run

In your terminal run the following to run the client with Rust’s cargo:

cargo install hnefatafl-copenhagen
RUST_LOG=hnefatafl_client=info hnefatafl-client

Note

At the moment their may be fairly regular updates. If you run into problems, make sure you are running the latest version.

Hnefatafl Org by David Lawrence Campbell is licensed under CC BY 4.0CC BY 4.0CC BY 4.0

Rules

Rules

From Copenhagen Hnefatafl with minor changes.

The Copenhagen rules were outlined 2012 by Aage Nielsen (Denmark), Adam Bartley (Norway) and Tim Millar (UK). English text and diagrams: Adam Bartley (Norway)

Based on the version that was last updated 21.12.2024.

Copyright © 1998-2025 Aage Nielsen, All Rights Reserved;

A: attacker
a: captured attacker
K: king
k: captured king
D: defender
d: captured defender
R: restricted space

1. Starting Board Position

Opening Game

2. First Turn

The attackers move first.

3. Movement

You can move to the edge of the board or another piece orthogonally:

Move

4. Capture

All pieces except the king are captured if sandwiched between two enemy pieces, or between an enemy piece and a restricted square. A piece is only captured if the trap is closed by the aggressor’s move, it is therefore permitted to move in between two enemy pieces. The king may take part in captures.

Captures

  ┌───────────┐ ┌───────────┐ ┌───────────┐ ┌───────────┐
11│R.........R│ │R.........R│ │R.........R│ │Rd........R│
10│...........│ │...........│ │...........│ │..↑........│
 9│...........│ │...........│ │...........│ │..A........│
 8│...........│ │...........│ │...........│ │...........│
 7│...........│ │...........│ │...........│ │...........│
 6│.....R.....│ │...A.R.....│ │..K..R.....│ │.....R.....│
 5│.....d.....│ │...d.......│ │..↓........│ │...........│
 4│.A→→→......│ │.Ad.dA.....│ │...........│ │...........│
 3│...........│ │...↑.......│ │..a........│ │...........│
 2│...........│ │...A.......│ │..D........│ │...........│
 1│R.........R│ │R.........R│ │R.........R│ │R.........R│
  └───────────┘ └───────────┘ └───────────┘ └───────────┘
   ABCDEFGHIJK   ABCDEFGHIJK   ABCDEFGHIJK   ABCDEFGHIJK

Doesn’t Capture

  ┌───────────┐ ┌───────────┐
11│R.........R│ │R.........R│
10│...........│ │...........│
 9│...........│ │...........│
 8│...........│ │...........│
 7│...........│ │...........│
 6│.....K.....│ │.....R.....│
 5│.....D.....│ │.D.D.......│
 4│.A→→→......│ │..↑........│
 3│...........│ │..A........│
 2│...........│ │...........│
 1│R.........R│ │R.........R│
  └───────────┘ └───────────┘
   ABCDEFGHIJK   ABCDEFGHIJK

Shield Wall

A row of two or more taflmen along the board edge may be captured together, by bracketing the whole group at both ends, as long as every member of the row has an enemy taflman directly in front of him.

A corner square may stand in for one of the bracketing pieces at one end of the row. The king may take part in the capture, either as part of the shield wall or as a bracketing piece. If the king plus one or more defenders are attacked with a shield wall, the attack will capture the defenders but not the king.

  ┌───────────┐ ┌───────────┐
11│R.........R│ │R.........R│
10│...........│ │...........│
 9│...........│ │...........│
 8│...........│ │...........│
 7│...........│ │...........│
 6│.....R.....│ │.....R.....│
 5│...........│ │...........│
 4│...........│ │...........│
 3│..D........│ │...........│
 2│..↓DDD.....│ │........AA.│
 1│R..aaaD...R│ │R....A→.KdR│
  └───────────┘ └───────────┘
   ABCDEFGHIJK   ABCDEFGHIJK

5. Restricted Squares

Restricted squares may only be occupied by the king. The central restricted square is called the throne. It is allowed for the king to re-enter the throne, and all pieces may pass through the throne when it is empty.

Restricted squares are hostile, which means they can replace one of the two pieces taking part in a capture. The throne is always hostile to the attackers, but only hostile to the defenders when it is empty.

The four corner squares are also restricted and hostile, just like the throne. The board edge is NOT hostile.

  ┌───────────┐
11│R.........R│
10│...........│
 9│...........│
 8│...........│
 7│...........│
 6│.....R.....│
 5│...........│
 4│...........│
 3│...........│
 2│...........│
 1│R.........R│
  └───────────┘
   ABCDEFGHIJK

6. King’s Side Win (Defenders)

If the king reaches any corner square, the king has escaped and his side wins.

Defender Wins

Exit Forts

The defenders also win if the king has contact with the board edge, is able to move, and it is impossible for the attackers to break the fort.

  ┌───────────┐ ┌───────────┐
11│R.........R│ │R.........R│
10│...........│ │...........│
 9│...........│ │...........│
 8│...........│ │...........│
 7│...........│ │...........│
 6│.....R.....│ │.....R.....│
 5│...........│ │...........│
 4│...........│ │...........│
 3│...........│ │....DD.....│
 2│....DD.....│ │....D.D....│
 1│R..DK.D...R│ │R...DKD...R│
  └───────────┘ └───────────┘
   ABCDEFGHIJK   ABCDEFGHIJK

7. Attackers Win

The attackers win if they can capture the king.

The king is captured when the attackers surround him on all four cardinal points, except when he is next to the throne.

If on a square next to the throne, the attackers must occupy the three remaining squares around him.

The king cannot be captured on the board edge.

The King is Captured

  ┌───────────┐ ┌───────────┐ ┌───────────┐
11│R.........R│ │R.........R│ │R.........R│
10│...........│ │...........│ │...........│
 9│...........│ │...........│ │...........│
 8│...........│ │...........│ │...........│
 7│.....A.....│ │...........│ │...........│
 6│....AkA....│ │.....R.....│ │.....R.....│
 5│.....A.....│ │....AkA....│ │...........│
 4│...........│ │.....A.....│ │....A......│
 3│...........│ │...........│ │...AkA.....│
 2│...........│ │...........│ │....A......│
 1│R.........R│ │R.........R│ │R.........R│
  └───────────┘ └───────────┘ └───────────┘
   ABCDEFGHIJK   ABCDEFGHIJK   ABCDEFGHIJK

If the attackers surround the king and ALL remaining defenders with an unbroken ring, then they win, as they have prevented the king from escaping.

Attacker Wins

The King is Not Captured

  ┌───────────┐ ┌───────────┐
11│R.........R│ │R.........R│
10│...........│ │...........│
 9│...........│ │...........│
 8│...........│ │...........│
 7│...........│ │...........│
 6│.....R.....│ │.....R.....│
 5│...........│ │...........│
 4│...........│ │...........│
 3│...........│ │...........│
 2│....A......│ │.A.........│
 1│R..AKA....R│ │RKA.......R│
  └───────────┘ └───────────┘
   ABCDEFGHIJK   ABCDEFGHIJK

8. Perpetual Repetitions

Deleted Rule

Perpetual repetitions are forbidden. Any perpetual repetition results in a loss for the defenders.

Added Rule

If the defender would repeat a board position, the move is not allowed.

9. Automatic Loss

If a player cannot move, he loses the game.

Artificial Intelligence

Artifcial Intelligence

I am working on making a reasonably strong artificial intelligence, but it is pretty weak at the moment. If you have the source package, You can run it via cargo run --release --bin hnefatafl-ai. See --help for what options you can pass it.

You’ll have to create an account for it first on whatever server you will be running it on. Run the client and log onto the server. Then, Create an account for your AI, prefixing the username with ai-.

It can also be run as a service for the Arch and Debian installs. Edit the file /etc/hnefatafl-ai-attacker.conf or /etc/hnefatafl-ai-defender.conf and add

USERNAME=username
PASSWORD=password

Don’t prefix the USERNAME with ai- here.

Then run

sudo systemctl start hnefatafl-ai-attacker

or

sudo systemctl start hnefatafl-ai-defender

If you want to change the settings for the AI further, you can edit /usr/lib/systemd/system/hnefatafl-ai-attacker.service or /usr/lib/systemd/system/hnefatafl-ai-defender.service and change the value of ExecStart.

By default this runs basic AI with a search depth of 4. The AI seems pretty weak if you go below 4. You can increase the depth, but the AI may run very slowly.

Be warned that by default this runs in parallel using all available CPUs. If you only want to use one CPU, you can pass --sequential.

Hnefatafl Org by David Lawrence Campbell is licensed under CC BY 4.0CC BY 4.0CC BY 4.0