Spanish 21 8-8 vs Ace Index Clarification

[Gronbog]

Hit -4>TC
Surrender -4<TC<-2
Split -2<TC.

Not quite. The surrender index takes precedence over splitting. So if you can surrender at -2 and -1, then you do so, otherwise you split.

Then to add to this confusion I will transcribe a paragraph (page 82), "Surrendering 8-8 versus Ace is a special case, when playing North American H17 and Pontoon. The NA H17 Index for surrender is -4, but when the true count reaches zero or above, splitting has a higher EV than surrendering, so we split.

At TC >= 0, this exception kicks in and you split.

There exists a similar situation for 17 vs A in 6D S17 LS blackjack using Hi-Lo where surrendering is correct across a range of true counts and the index for standing vs hitting falls within that range. I'm sure that Don and I are not the only ones to know this, but FWIW, detailed information will be released as part of our upcoming book on index play.