So I noticed that my neighborhood store which gives me the most match-play coupons, allows for these coupons to be used on Spanish 21 (many other local stores don't allow match play coupons to be used on SP21). Not only that, but there is this sweet deal- if you use it on the game, and surrender, they take your match-play coupon only, but you get to keep your chip. Using the standard valuation of 50% of value for a match-play coupon (so a $50 match play coupon, is actually worth $25, give or take, in cash), this means you can surrender and only lose 33.3% of the overall bet. As I get lots of Match Play coupons each time I play, it is worth knowing the proper surrender strategy to use.....

Does anyone know of a chart similar to this for blackjack (https://wizardofodds.com/games/blackjack/appendix/1/), that shows the EV for each hand at S17 Spanish 21? Then I can just look at which hands have an optimal hit/stand decision that is under -0.333, and surrender those, when using my coupon.

The easiest answers, are when the original optimal play involves standing. Per Katarina Walker's book, page 54, in a S17 game, the dealer busts 31.5% (less than 33.3%) of the time, so with a match-play coupon, surrendering when one should otherwise stand with a stiff total (such as 15 v 2 and 16 v 2) is warranted. Against a 3, the dealer will bust 33.5% (more than 33.3%) of the time, but page 134 shows that when the count is positive (using her count, but the same would likely apply to any other reasonable counting system), the busting percentage is slightly higher than that. Because I would only use the match play when the count is slightly positive, I will not surrender instead of standing against a dealer 3.

The irony of my asking this question, is that I actually asked something similar six and a half years ago (I was counting cards at Spanish 21 before it was "cool" to do so....)- kudos to Assume_R for giving me an answer, for each True Count (!) for a few situations- see the link from Blackjackinfo.com- ("https://www.blackjackinfo.com/community/threads/spanish-21-expected-return-charts.22380/"). It shows that surrendering 15 v T, 16 v 9,T,A, 17 v T,A is the correct play (since the EV for each of these is far far worse than -.333), and 15 v 9,A and 16 v 7,8 is almost surely the right play, based on this information. I'm wondering about 12 v 7,8,9,T,A, 13 v 7,8,9,T,A 14 v 2,7,8,9,T,A, 15 v 7,8, 17 v 8,9, and even 18 v 9,T,A. Of course, I'm fine with an answer for this using an infinite deck model, and no counting. That question from almost seven years ago seems silly now, as it would only save me a quarter (see the thread)- but with a $50 match play coupon and $50 in chips, this answer would make a much bigger difference. Any help would be appreciated. :-)

I really try not to ask questions on this forum, and find the answers myself, but am stumped here. Anyone else play Spanish 21 with Match Plays? Anyone have a simulator for the game, or one for blackjack, where the tens can be removed, that can provide the EV figures for the questionable hands, or at least whether they are above or below -0.333?