Convincing Control is a card control or cull, named by Ed Marlo, which secretly gets a selected card from a face down, in the hands, spread to the bottom of the deck while in the act of closing the fan.
Marlo based on a variation of his bottom control "The Prayer Cull" that appeared in The New Tops (June, 1966) it was first published in Ed Marlo in Hierophant No. 3 (1970). Marlo was said to have created it based on a description told to him by Alton Sharpe (not the method, just what he had seen from a spectators point of view) about a move he had seen Larry Jennings do.
The same basic control, which many now refer to as the "Hofzinser Spread Cull", was also described in a Hofzinser card problem "Synonymous Thoughts" (First Method) which was first printed in English in the The Sphinx for April 1922.
Ackerman wrote in his book, Magic Mafia Effects (1970) that the technique was "a variation of Ed Marlo's improvement of the Hofzinser card pass" and called it "A Card Pass." (p. 29)
- "Synonymous Thoughts" (First Method), printed in English in The Sphinx, Vol. 21, No. 2, April 1922, page 60.
- "Card in the Aces" trick (part eight of Willane's Methods for Miracles series) by Edward Victor (1952) Victor describes the same method up to the point of closing the spread.
- Convincing Control by Ed Marlo in Hierophant No. 3 (1970)
- "Immediate Bottom Placement" by Larry Jennings in The Classic Magic of Larry Jennings (1986).
- The Hofzinser Spread Control in Magical Arts Journal Vol. 2 No. 7&8 (1988)
- The Convincing Control in Card College, Vol. 3 (1998)
- Backslip Control by Jean Hugard in Royal Road to Card Magic (1948)
- "Ackerman Varies Kelly" in The Esoterist (1971)
- New Convincing Control by Allan Ackerman in Here's My Card (1978)
- Marlo's Convincing Control Technique by Ron Bauer in Fair & Sloppy, Ron Bauer Private Studies Series, No. 9 (1998; 2002, pp. 15-22).
- The Losing Control by Lee Asher & Allan Ackerman in Hand Jobs (2001)
- Secret Moves in Marlo's Magazine, Vol. 3 (1979)
- On the Spread Cull by Jon Racherbaumer & New Approach Convincing Controls in Marlo's Magazine, Vol. 5 (1984)
- Jennings '67 (1997)