Santase Game Engine

Santase (also known as 66, Сантасе, Sixty-six or Sechsundsechzig) is a well-known card game in Bulgaria, also played in Germany and Austria (as Schnapsen).

It is a fast 6-card game for 2 players, played with a 24-card deck consisting of the Ace, Ten, King, Queen, Jack and Nine of each suit.

The core engine in src/Santase.Logic is published as the SantaseGameEngine NuGet package (MIT, currently version 3.0.0, targeting .NET 10). Everything else in the repository is AI players, UIs and a benchmarking simulator built on top of that engine.

Screenshot

The cross-platform .NET MAUI app (src/UI/Santase.UI), playing against the Smart Player:

Rules of the game

The full rules as implemented by this engine are documented in RULES.md.

External references (these describe different variants and do not match this engine exactly):

• Wikipedia (EN): https://en.wikipedia.org/wiki/Sixty-six_(card_game)
• Wikipedia (BG): https://bg.wikipedia.org/wiki/%D0%A1%D0%B0%D0%BD%D1%82%D0%B0%D1%81%D0%B5

Repository layout

src/Santase.sln                 Visual Studio 2026 solution

src/Santase.Logic               The engine — the SantaseGameEngine NuGet package
src/AI/Santase.AI.DummyPlayer   Baseline legal-random players
src/AI/Santase.AI.SmartPlayer   Heuristic AI player
src/AI/Santase.AI.ClaudePlayer  AI player (incl. an optional neural variant)
src/AI/External/*.dll           Third-party binary AI players (no source)
src/UI/Santase.UI.Console       Human-playable console UI (.NET 10)
src/UI/Santase.UI               Cross-platform .NET MAUI app (Android / iOS / macOS / Windows)
src/Tests/Santase.Logic.Tests             xUnit tests for the engine (255 tests)
src/Tests/Santase.AI.SmartPlayer.Tests    xUnit tests for SmartPlayer
src/Tests/Santase.AI.ClaudePlayer.Tests   xUnit tests for ClaudePlayer
src/Tests/Santase.Tests.GameSimulations   Parallel AI benchmark / game simulator

Source code requirements

• .NET 10 SDK
• Visual Studio 2026 (or any editor with the .NET 10 SDK; Rider / VS Code work too)
• The cross-platform Santase.UI MAUI project additionally needs the MAUI workloads (dotnet workload install maui) and the relevant platform SDKs. It is not required to build or use the engine.

Build, test, run

# Restore + build the whole solution (Release recommended).
dotnet build src\Santase.sln -c Release

# Run the unit tests (xUnit).
dotnet test src\Santase.sln -c Release

# Run the AI benchmark / game simulator (the primary regression check for AI changes).
dotnet run -c Release --project src\Tests\Santase.Tests.GameSimulations\Santase.Tests.GameSimulations.csproj

# Play against the AI in the console.
dotnet run --project src\UI\Santase.UI.Console\Santase.UI.Console.csproj

The Santase.Logic library is extensively unit tested (255 tests in Santase.Logic.Tests).

NuGet package: https://www.nuget.org/packages/SantaseGameEngine