Continuity mistake: Between shots, the bodies of both Kathy and the Kid change positions on the floor. Kathy's has moved away from the stairs, and the Kid's reverses directions.
Continuity mistake: In full shots, the judge's cigar is in his mouth. Every time a close-up is intercut, the cigar is in his hand.
Continuity mistake: Twice in this episode (once in the saloon and once in the sheriff's office), Number 6's coat is unbuttoned when he's inside, but has instantly buttoned itself up when he runs outside.
Continuity mistake: The drink Kathy brings the Kid changes positions on the table between takes. She places it on top of the small book, but it moves itself to the larger book, then back to the small one again, and so on.
Revealing mistake: When the red handkerchief is tied to Number 6's hand, Patrick McGoohan's wedding ring is visible in the close-up.
Continuity mistake: While Number 6 is being dragged behind the horse, a red bandanna tied around his hand disappears and reappears several times between shots.
Continuity mistake: While Number 6 is in the jail cell, he lights a cigar and starts blowing smoke. Just a few shots later, the smoke has vanished and he lights the cigar again.
Continuity mistake: Number 6 is sitting in jail rolling a cigarette. In the long shot, you can see that he's just exhaled a cloud of cigarette smoke. But, in the next shot, he has just finished rolling the cigarette and has yet to light it. (00:11:10)
Continuity mistake: At the final shoot-out, the Kid's hat lands and settles right next to his head after he falls. When Number 6 walks past him a few moments later, however, the hat has somehow moved itself more than a foot away.
Continuity mistake: The judge has two glasses in front of him on the bar. When the shot changes, there's just one glass.
Continuity mistake: In the saloon, between close-ups and cutting back to the master shot, the glasses in front of the men at the bar change positions repeatedly.
Answer: It's even more obvious than you think, you know who number 1 is in the very first episode. When 2 replies to the question "who is #1?" Change the way he answers from you are number one (in the monotone or accented answer to, "You are, number 6. The comma gives you the answer. #6 is #1. It's the tone of the answer.