Why is this a good spot to c/r ?
Meh, my initial recommendation of a c/r was partly based on my initial impression that a 3bet might be too thin, but w/e, here's a couple arguments in favor of a c/r:
- a lot of your range just HAS to check this river. The ultimate scare card just hit, and you have to adjust to how that affects your and your opponents ranges. A lot of your value hands just turned into bluffcatchers, almost all of your bluffs just got there. BB should have had more value hands than bluffs on the turn, but a lot of those value hands just can't valuebet anymore. Whereas on a blank river the BB should be betting the majority of his range, on this river the default play should be to check, (either c/f or c/c). This should be balanced by c/r-ing a couple strong hands. Theoretically, your c/r range should be mostly made up of hands that are strong enough to c/r/cap, hands that aren't quite strong enough to b/3bet, and bluffs.
In this particular case, c/r almost certainly maximizes your value versus:
hands that were bluffcatching on the turn but can't call anymore: ( mostly A hi, bottom pair), since villain might (should!) turn some of these into bluffs.
hands that will valuebet more or less thinly, but are unlikely to raise river: mostly 6x, some rivered 2pairs, 99, mayyyyyybe Jx (which will probably raise, whether or not that's good)
on the other hand, c/r might actually SAVE you a bet (compared to b/3b), if you run into a better flush
on the downside, there's quite a few hands that b/3b gets more value from:
mostly Jx, but also some A9 type of hands that might pay off a river bet (even tho that looks kinda bad), but won't bet if checked to.