Open jamming with 20BB is very deep and typically not recommended, unless its a situation, where we can apply a lot of ICM-pressure to the opponent. The main situation for it is blind vs. blind, where open jamming from SB takes away the disadvantage of being out of position. But other than that 20BB is just a really awkward stack size for small pairs, and there is nothing wrong with simply dumping them even in late position.
Lets say for instance we are on a final table, we are on BTN, and we look down at 33. We have 19BB, and two good aggressive players in the blinds each have 40-50BB. UTG+1 is the table short stack with 4BB. If we open jam here, its an ICM-disaster, if we get called and lose, and we are not getting a good risk/reward.
If on the other hand we min-raise, the players in the blinds will jam on us with a lot of hands, in which case we need to fold. Or BB will defend by calling, and then our hand play really poorly postflop with short stacks. On a lot of boards we will need to check back, and then big blind with his much bigger stack can bet and take it down, weather he has it or not. So we dont have any realistic way to make money by getting involved with 33, and therefore we should just fold and wait for a better hand or for UTG+1 to bust, so we get a payjump.
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