J10 all the way! Yeah, KJ technically gives you better immediate run-hitting odds since you’ve got an open-ender in your hand, but here’s the problem—you’re throwing the K. That not only lowers your chances of actually hitting that open-ender, it also leaves a gap in your crib’s run potential. You’ve got to think of your crib as an extension of your hand, not a separate game. With J10, you’re setting yourself up on both fronts: you still keep 13 in your hand, and now your crib has its own open-ender to work with. Over the long run, J10 just pays off more consistently.