Slowplaying Versus Check-Raising

Slowplaying is not the same thing. It is playing a hand weakly on one round of betting in order to suck people in for later bets. Typical slowplays are to check if there has been no bet or just call a bet rather than raise. In other words, you take no action beyond what is necessary to stay in the pot. You give nothing away about the strength of your hand.
When you check-raise you usually want to reduce the number of your opponents, but when you slowplay you are Crying to keep as many players in the pot as you can, expecting to collect later bets from them as a result of your early deception. Obviously, since you are not worried about having many players in the pot and are not particularly concerned about giving them free cards, you must have a very strong hand to slowplay - much stronger than a hand with which you would check-raise. In seven-card stud it might be three-of-a-kind on the first three cards or a flush or full house against one pair. In hold 'em it might be the top set of trips after the flop with no possible straight or flush draw showing. In draw lowball it might be something like a pat