Chiron 4 released

Chiron 4 is about 70 points stronger than Chiron 3.


Here’s a list of the main changes:

  • improved automatic tuning of the evaluation
  • improved evaluation of passed pawns, mobility, opposite bishops endings
  • improved forward pruning in the search
  • improved LazySMP for parallel search
  • support for Windows Processor Groups (more than 64 threads can now be used)
  • NUMA optimization (new UCI and Winboard options “NUMA”)
  • minor speed optimizations
  • fixed a pondering bug
  • fixed two time management bugs under the Winboard protocol

Chiron 4 is available for Windows and Android.
Buyers of the Windows version will also receive a code to get the Android one for free.


Chiron 2/3 Customers can buy Chiron 4 with a discount through the link they have reiceved. Whoever has bought Chiron 3 in the last month will receive Chiron 4 for free.