The guys from opengammon.com released a backgammon on their own: the hedgehog.
Actually, the hedgehog is at least four different engines, with names like Aureus or Fox that you can play against, and a supposedly ultra-ultra-human engine to analyze matches for you that supposedly plays even better than Extreme Gammon and the other leading PC apps. And it comes with a nice free tier and expensive paid tiers that set you back 60 Euros or even 120 Euros a year to get „Every model we run, including the frontier networks no other plan can select“.
All very confusing.
But the Fox engine and the Aureus engine play a strong game of backgammon. It‘s still too early to tell, but in the first four 5 pt matches I played against it it both the engines played at world champion level of about PR 2.2. Nice. And their web UI is beautiful and works on phones and PCs.
Review will follow soon.
Update: by now I have played matches worth 30 games against the 4 engines and have BGBlitz analyze them. Aureus (15 games) seems to play at slightly below PR 2, the two Fox versions similarly, maybe a bit worse?, the Default engine also a bit worse, but apart from Aureus (I like the name so somehow I prefer playing it 🙂 ) it is very preliminary.
Why Hedgehog has 4 engines of nearly identical strength is still unclear.