Pokayoke is infact a simple concept which explains the use of simple mechanisms that stop mistakes being made by manufacturing operators without requiring concentration by the operators. The term “PokaYoke” was popularised by Shigeo Shingo through his book “Zero Quality Control: Source Inspection and the PokaYoke System”. Shingo points out that mistakes will always be made, but if PokaYoke’s are implemented then mistakes can be prevented from becoming defects. By eliminating the defect at source the cost of mistakes/defects can be substantially reduced.
Here is a link to a tutorial on Mistake-proofing, Poka-Yoke, and ZQC by John R. Grout and Brian T. Downs:
http://www.campbell.berry.edu/faculty/jgrout/tutorial.html
http://www.campbell.berry.edu/faculty/jgrout/pokayoke.shtml