They double when the player has soft 13 with Ace and 2 or soft 18 with Ace and 7. Doubling down has some general rules.
https://script.jumgoo.com/forum.php?mod=viewthread&tid=10927&extra= http://horsecity.ru/phpBB3/viewtopic.php?f=7&t=249824 http://oldsite.giessen46ers.de/fantalk/viewtopic.php?f=1&t=250531 http://wirtualnapolityka.cba.pl/showthread.php?tid=10810 http://1.s.2.free.fr/viewtopic.php?f=18&t=558542 http://1.s.2.free.fr/viewtopic.php?f=18&t=534906 https://www.ww2.site/forum/viewtopic.php?t=67220 http://horsecity.ru/phpBB3/viewtopic.php?f=28&t=255091 https://muchroom.ng/index.php?topic=57742.msg67516#msg67516 http://biopharmamash.com/viewtopic.php?t=1941002 http://47.88.101.141/forum.php?mod=viewthread&tid=478327&extra= http://mirosovak.edoras.cz/viewtopic.php?f=3&t=556655 https://planeswalkers.org/viewtopic.php?t=23889 https://67farms.st/viewtopic.php?t=33125 https://67farms.st/viewtopic.php?t=12176 http://myweed.rocks/viewtopic.php?t=56533 https://refugeesfog.com/viewtopic.php?t=657993 http://biopharmamash.com/viewtopic.php?t=1909625 http://vortex.mx.free.fr/forum/viewtopic.php?f=38&t=23107&sid=f7f0a8d034a7c1b942d00fce2c204c06 http://myweed.rocks/viewtopic.php?t=91810 https://ufr-2020.front5.picapo.net/forums/viewtopic.php?pid=430891