user1627: I have file Rybka.exe and when I use it for the first moves, it always goes Nf3 or Nc3 only (even at strength 1000 and depth 1). I assume that is because it doesn't have opening book assigned (?) to it. How does one connect opening books in .ctg (or other?) formats to the chess engine? I do not want to get some GUI, but rather understand how it is done.

user825: I don't have Rybka 4 but I do have the free version (Rybka 2.3.2). Rybka 2.3.2 doesn't support engine book. To verify this, open the engine in command, then type "uci". Look at how I did it.
Look the UCI options, we have one for multi-pv and others. But there is nothing for an opening book. If the engine doesn't support an opening book, you have to rely on a GUI to do it, for example, Fritz.
On the other hand, if you do the same thing to Stockfish, you'll see a Book options where you can specify path to your book be used by the engine.


1627: <p>I have file Rybka.exe and when I use it for the first moves, it always goes Nf3 or Nc3 only (even at strength 1000 and depth 1). I assume that is because it doesn't have opening book assigned (?) to it. How does one connect opening books in .ctg (or other?) formats to the chess engine? I do not want to get some GUI, but rather understand how it is done.</p>
 825: <p>I don't have Rybka 4 but I do have the free version (Rybka 2.3.2). Rybka 2.3.2 doesn't support engine book. To verify this, open the engine in command, then type "uci". Look at how I did it.</p>

<p>Look the UCI options, we have one for multi-pv and others. But there is nothing for an opening book. If the engine doesn't support an opening book, you have to rely on a GUI to do it, for example, Fritz.</p>

<p>On the other hand, if you do the same thing to Stockfish, you'll see a Book options where you can specify path to your book be used by the engine.</p>

<p><img src="https://i.stack.imgur.com/a3C0L.png" alt="enter image description here"></p>
