How to use Clover Chess Engine

Clover is a UCI (Universal Chess Interface) chess engine created by Luc Metehau. It is a world-class competitor, often ranking high on rating lists like CCRL and SP-CC with an Elo rating well above 3500. However, Clover is just the “brain” of the chess player. It does not have its own window or buttons. To use it, you need a “body” or a GUI (Graphical User Interface).

This guide will walk you through everything from downloading Clover to configuring it for professional-level analysis.

1. Prerequisites: Choosing Your “Chess Body” (GUI)

Because Clover is a engine-only file (an .exe on Windows), you must download a GUI to interact with it. Here are the most popular free options:

• Arena Chess GUI: Highly customizable and the classic choice for engine testing.
• BanksiaGUI: Modern, sleek, and very fast.
• Cute Chess: Often used for running tournaments between different engines.
• Nibbler: A beautiful interface specifically designed for engines that use neural networks.

2. Downloading and Installing Clover

To get the latest version of Clover, follow these steps:

1. Visit the Official Source: Go to the Clover Engine GitHub repository.
2. Go to Releases: On the right side of the page, click on “Releases” to find the most stable version (e.g., Clover 7.0).
3. Choose the Right Binary: You will see several files like avx2, bmi2, or sse41.
   • AVX2/BMI2: Use these if you have a modern CPU (Intel 4th Gen/AMD Ryzen or newer). They are the fastest.
   • SSE41: Use this if you have an older computer.
4. Extract the Files: Download the .zip file and extract it to a folder on your computer (e.g., C:\Chess\Clover).

3. Connecting Clover to Your GUI

Once you have the engine file and a GUI, you need to “introduce” them to each other. Here is how to do it in Arena (the process is similar in all GUIs):

1. Open Arena.
2. Go to the Engines menu at the top and select Install New Engine.
3. Navigate to the folder where you extracted Clover and select the .exe file.
4. Arena will ask if you want to start the engine. Click Yes.
5. Clover is now ready! You should see its name and its evaluation (numbers like +0.45) at the bottom of the screen.

4. Understanding Clover’s “Brain”: NNUE

Clover uses a technology called NNUE (Efficiently Updatable Neural Networks). This allows it to combine the lightning-fast calculation of traditional engines with the “deep intuition” of neural networks.

When you run Clover, it typically looks for an external network file (often ending in .nnue). In recent versions, this network is usually embedded inside the engine, meaning you don’t have to worry about downloading a separate file—it works “out of the box.”

5. Advanced Settings (UCI Options)

To get the most out of Clover, you can right-click the engine in your GUI and select Configure or Engine Parameters. Here are the key settings you should know:

Hash (Memory)

The Hash table stores positions Clover has already seen so it doesn’t have to calculate them again.

• Small (16-64 MB): Good for quick games or weak computers.
• Large (1024-4096 MB): Best for deep analysis of complex positions.
• Rule of thumb: Use about half of your total RAM.

Threads

This tells Clover how many CPU cores to use.

• If you want the engine to be as strong as possible, set this to the number of physical cores your PC has.
• If you want to use your computer for other things while the engine is running, leave 1 or 2 cores free.

SyzygyPath (Endgame Knowledge)

Clover supports Syzygy Tablebases. These are files that tell the engine exactly how to win or draw any endgame with 3 to 7 pieces left on the board.

• If you have these files downloaded, paste the folder path into the SyzygyPath box. This ensures Clover never makes a mistake in the endgame.

6. How to Use Clover for Improvement

Playing against Clover is like playing against a god—you will lose every time. Instead, use it as a coach:

A. Analyzing Your Games

Load a PGN file of your game into the GUI. Turn on Clover and look for the Evaluation Bar.

• Positive (+) numbers: White is winning.
• Negative (-) numbers: Black is winning.
• Blunder Detection: If the score jumps from +1.5 to -2.0 in one move, you just made a massive mistake. Ask Clover to show you the “Line” (the moves it would have played instead).

B. Finding “Only” Moves

In complex tactical positions, Clover can find moves that seem impossible to humans. If you are stuck in a puzzle, let Clover run for a few minutes. As it reaches a higher Depth (e.g., Depth 30 or 40), it will uncover the hidden truth of the position.

C. Testing Openings

If you have a new idea in the Sicilian Defense, play it against Clover. It will ruthlessly exploit any weakness in your theory, helping you patch up your opening repertoire before you play against humans.

7. Troubleshooting Common Issues

• Engine Crashes: Usually happens if you choose a version your CPU doesn’t support (e.g., trying to run avx512 on an old laptop). Try the sse41 version.
• Engine is Slow: Check the Threads setting. Also, ensure your laptop is plugged in; many laptops throttle CPU speed when on battery.
• No Moves Displayed: Ensure you have clicked the “Analyze” or “Infinite Analysis” button in your GUI.

Feature	Recommended Setting	Purpose
Protocol	UCI	Standard communication with GUI
Hash	1024 MB+	Faster search for long analysis
Threads	Max minus 1	Balanced performance
Strength	3500+ Elo	Grandmaster-level precision
Best For	Deep Analysis	Finding tactical “truth”

Frequently Asked Questions (FAQ)

What is Clover, and is it a chess program I can play against directly?
Clover is a UCI chess engine, not a standalone program. It does not have its own interface, so you must use it with a chess GUI such as Arena, BanksiaGUI, or Cute Chess.

Which GUI works best with Clover?
Clover works with any UCI-compatible GUI. Arena is a popular choice for analysis and testing, while BanksiaGUI offers a more modern and faster interface. Cute Chess is preferred for engine tournaments.

Which Clover version should I download for my computer?
Choose AVX2 or BMI2 if you have a modern CPU (Intel 4th Gen or newer, or AMD Ryzen). If your computer is older, use the SSE41 version to avoid crashes.

Does Clover require a separate NNUE network file?
No. In recent versions, Clover includes the NNUE network internally, so it works out of the box without downloading any additional files.

How much Hash and how many Threads should I use?
A good rule of thumb is to set Hash to about half of your available RAM and Threads to the number of physical CPU cores, leaving one core free if you want to use your computer at the same time.

Is Clover suitable for beginners?
Clover is extremely strong and not meant for fair play against humans. It is best used as an analysis tool to review games, find blunders, and study openings.

Why is Clover running slowly or not showing any moves?
Make sure you have started Infinite Analysis in your GUI and that your Threads setting is correct. On laptops, performance may drop when running on battery power.