Looking for a chess engine that instead of playing the best move randomly chooses among the best moves? Of course this should be subjected to some rules; something like &quot;play any move that's not bellow 0,70 the best move&quot;, or something similar.
My idea is to use such an engine in order to play some unorthodox openings without needing an opening book.
For example, say I want to play some games as White trying 1.e4 e4 2.a3. I'm sure there are many good moves for black's second move, so I'd like the engine to &quot;choose&quot; from several of them, instead of always playing the best one.
Kudos if this behavior could be limited to a fixed number of moves -so you get some variety in the opening but you want it &quot;full power&quot; on middle and endgame.
There are few engines that are capable of such thing. One name that I can recall is the old Spark UCI engine by Allard Siemelink.
Very aggressive engine with twistable attacking parameters.
It has a feature called MultiPVMargin which enables you to set certain number difference between the PV (Principle Variations) measured in centipawn.
For example if your best calculated variation in certain position is measured as +1 for white and you want the engine to play something less &quot;valuable&quot; than that, you can set the MultiPVMargin to a 100 so that the engine looks for a different variation within the 100 centipawn difference.
You can find older versions of the Spark engine that are available for free download.
Hope this was the answer you were looking for!