Hi Lucky River. That's a good question. As for me, I open raise, because I don't want to run all other players out with an allin. However, many will tell you to move allin, and hope you get at least one or two callers. But still, letting players see the flop, can bust AA and KK really easy. So the move is up to you, GL in any games you play today
To me this is contingent on the structure. If this is a tournament where 15 BBs is a fairly deep stack (can happen late) I much prefer open raising and trying to induce action. If this is a structure where its turbo or super turbo and blinds are going up really quickly or very soon then I think you can go either way but I prefer jamming in that spot. You would be jamming with 99-JJ here and not open raising so your AA or KK would be a little more disguised but depends too on if you are playing against opponents who notice things. 15BBs is that edge where you can tend to go either way, even slim it down to 12 BBs and I think it is better to jam all hands that you want to play instead of trying to induce.
I also think the other stack sizes at the table matter. I mentioned above where if 15BBs is deep for the tournament but if you are at a table where there are multiple 60BB stacks and above I think its better to get it in as big stacks and small stacks will tend to call it more. Its the medium stacks that usually will not want to make a big call of an all in since they are worried about becoming a small stack.
Based on the depth of 15bbs it is probably best to simply shove All-In right away with AA or KK. It doesn't give the chance for something like an Ace-rag to see the Flop cheaply and bust our KK when they Flop an Ace when they would have folded to our preflop shove.
However, in a few spots against the right opponent - you might be able to open-raise and then go All-In. Perhaps against someone wary of calling All-Ins but with no issues about calling an open raise, or perhaps against someone constantly shoving over your open-raises but folding to your original raises.
Generally speaking you won't have these trickier or less informed players though. Usually I'd shove preflop instantly. Whatever you decide for this spot though, stick with it. Another reason to shove right away is because we probably don't want to open-raise with so few big blinds and then fold later in the hand. If you are committing all of your chips, then why not just do it right away? Why wait? As long as you can get it all in the middle, or extract maximum value, then it doesn't matter a ton, so might as well go in earlier to get some fold equity along with it
Summary: Usually shove All-In for this spot, but a few tricky players or spots may come up where otherwise may be justified.
We aren't typically wanting to raise and then fold here. Why? Save a few chips...save it for what? Might as well get it in when we are almost certainly ahead.
at early position with 15bb 3x raise seems scary than pushing all in to other players probably. If someone catches good hand they will either shove or call your all in no matter what. You better focus on the late position player's stacks. If the SB or BB is deep then you might get them calling your raise with an average hands too.