No, this article is not about foot tapping signals, suspect thinking pauses and coded coughing or chin scratching. That is where non bridge playing journalists focus on - on the rare occasion they do pay attention to bridge, that is.
Take that popular sports show on Dutch TV in 2004: it had a bridge item, even featuring a few players of the Dutch Open bridge team - among which Bridgevaria's Sjoert Brink if I recall correctly. The reason was Netherlands had won the silver medal at the Istanbul Olympiad.
A good opportunity, you think, for the (highly acclaimed) show host to ask the players about their fascination for bridge, to ask them to give a general idea about the game, to ask them what moves top players?
Well, you thought wrongly. The full time the item lasted (some three and a half minutes), the subject was cheating. With stereotypical questions like 'How do they do it, this illegal signalling, do they scratch their chins or what?' the show host confirmed all prejudices about bridge. And so viewers were none the wiser afterwards about our fantastic mind game. A missed opportunity.

But alright, I wrote that is not what this article is about. Then what is it about? Legal deceit, or: deceptive plays. To many these are the crème de la crème of our great game.

By playing one or more falsecards a player can delude his opponent(s) with the image of a possible but non-existent distribution. That opponent who, so it seemed, 'could not go wrong' now suddenly has a choice of plays. He might choose the play that would succeed if the distribution is like the falsecarder wants him to believe. If he does, he is not necessarily being stupid since that distribution might really exist.
A simple example of such a technical deceptive play, by a defender in this case:

		♠	A 8 3 2
♠	4			♠	J 9 7 5
		♠	K Q 10 6

South is declarer and starts off with the ♠K. If East contributes the 'normal' ♠5, his lowest, South has no choice: he continues with the ♠6 to the ♠A since if the last three spades, ♠J97, are in one hand, South can escape a loser only if they are with East. South therefore 'cannot go wrong': after seeing West show out in that second round, he finesses East's ♠J.
Now see what happens if in the first trick East plays the ♠9 under the ♠K. Suddenly South can also escape a spade loser if West holds four spades to the jack, since West would then have ♠J754. South now could decide to play the ♠Q in trick two. That would be winning if East now showed out: South then would continue with the ♠6 to the ♠8.
In this case he would have swallowed the bait, but his decision certainly was not stupid: after all East's ♠9 could have been a genuine singleton.

Sometimes I try a 'Zia Mahmood' myself (Zia is the king of deceptive plays) but the results are errr... varying. But in the rare case I succeed, I make a note of the deal (mindful of the introduction of my earlier column 'An unbelievable contract - 1').
Take this deal from a Norwegian league match. As South I held:

My partner opened a weak 1NT (12-14). We did not play transfers and bid gameforcing hands via 2♦, gameforcing Stayman.
So I had to choose between 3♥ (invite) and 4♥. I convinced myself my partner could not be expected to accept an invite holding a 'suited minimum' like ♠AJx ♥KJx ♦Kxx ♣xxxx. Hence my overbid of 4♥.
West led the ♣10:

N/-		♠	A 10 4
		♥	K 3
		♦	K 10 6
		♣	K 9 7 5 2
		♠	K Q 7 6
		♥	Q 9 8 7 4 2
		♦	Q 7
		♣	J

¹ 12-14 points
² we did not play transfers

This looked bad. I had to lose three aces and most of the time a second trump trick. And then there was that fourth spade.
It seemed that West would have to have ♥A doubleton, since the only play for one heart loser was a heart to the ♥K followed by ducking a heart. But in view of dummy's ♣9 West's ♣10 lead was clearly a singleton or doubleton, which made it less likely he had the short trump suit.
Going up with the ♣K was certainly pointless: I knew West, he was not the adventurous type to underlead an ace. So I played a small club in dummy and East won with the ♣Q. After seeing my ♣J, he thought for a while. Finally he continued with the ♣6.

If West's ♣10 was a singleton, I could trump with the ♥9, hoping East to hold precisely ♥J106 or ♥J105. But the chance of such a distribution was too slim to play for. Furthermore the ♣10 did not look like a singleton to me, since it took East so long to return that ♣6: he obviously was not sure. 
So I hoped East had made the mistake of taking my ♣J for a falsecard. West was going to follow suit then and dummy would win (if West would ruff after all, I hoped it to be a sure trump trick, limiting my losses to one down).
But what was I going to discard? I had no loser to throw on that ♣6. Then I spotted the opportunity for a deceptive play: what if East had the ♥A doubleton? In that case the short trump suit and the long club suit were in one hand, a fair chance. So I threw the ♦Q!

Indeed West followed suit, with the ♣3, and dummy's ♣7 won. West gave my ♦Q and his partner an irritated look. East seemed to take it stoically but I sensed that he too thought I had discarded the bare ♦Q.
I crossed to the ♠K in my hand (East ♠3, West ♠2) and played the ♥2 (West the ♥5) to the ♥K. If it would have won, I would have had to hope for the ♥A doubleton in West after all (by playing the ♥3, ducking in hand), unlikely as that may have been.
But East won with the ♥A and again played a small club (not the ♣A: that would make two of North's clubs good and give me the contract if I had started with ♠Kxxx ♥Q9xxxxx ♦Q ♣J). This was psychologically fully understandable: after his earlier failure to do so, East was determined to promote a trump in West!
I now discarded the ♦7, my genuine diamond loser, and West looked like he had seen a ghost. Finally he ruffed with the ♥6 and returned the ♥J. East contributed the ♥10! It had worked: West had ruffed my loser with his natural trump trick!

I won with the ♥Q and now had to avoid the possible spade loser. I knew five cards in West (three hearts and two clubs) and seven in East (two hearts and five clubs). This made it a bit likelier West had length in spades (including the ♠J) than if I had not had that information. Enough to finesse the ♠J over West?
Fortunately I did not have to choose. Since East had the ♣AQ and the ♥A, West was sure to have the ♦A (with that card East would have had 14 points, enough to double the weak 1NT). So I reeled off my trumps. With the last one to go, the situation was:

N/-		♠	A 10
		♥	-
		♦	K
		♣	K
		♠	Q 7 6
		♥	4
		♦	-
		♣	-

Naturally neither East nor West had thrown his ace so far. When I played the last trump, the ♥4, West still did not discard his ♦A. Therefore I threw dummy's ♦K, knowing West now held the ♦A and thus two spades at most.
East clung on to his ♣A, so after this trick he was known to hold that card and thus two spades at most. I played the ♠6 to the ♠A and the ♠10 to the ♠Q and knew for certain the ♠7 would win the last trick.
For a little while I felt like being Zia Mahmood...

PS: The finesse of the ♠J over West would have failed, though he did have four spades. This becomes clear from the situation with the last trump still to play (red cards have been played):

N/-		♠	A 10 4
		♥	K 3
		♦	K 10 6
		♣	K 9 7 5 2
♠	9 8 5 2			♠	J 3
♥	J 6 5			♥	A 10
♦	A J 8 2			♦	9 5 4 3
♣	10 3			♣	A Q 8 6 4
		♠	K Q 7 6
		♥	Q 9 8 7 4 2
		♦	Q 7
		♣	J