Retrograde Solving

Not to be confused with Backsolving, a strategy for solving feeder puzzles after having solved the meta.

Retrograde Solving is a holistic solve path element in which solvers are presented with the final state of something and need to figure out what it started as. This element is often combined with Transformation Chain puzzles.

Background

Retrograde Solving has some parallels to detective work in the mystery fiction genre, where a detective has to deduce a sequence of events that led to a final scene. Perhaps the first class of Retrograde Solving puzzles are retrograde analysis chess problems, with noted chess composers such as Sam Loyd creating retrograde analysis problems as early as 1859. The first retrograde analysis book of chess problems, Retrograde Analysis by Dawson and Hundsdorfer, was published in 1915.

Puzzle Application

TO DO

Strategy

TO DO

Notable Examples

• An Erratic Puzzle (Galactic Puzzle Hunt 2019) - Presented like a series of errata for a relatively small puzzle, it requires solvers to reverse all of the changes in order to reach the 'original puzzle'. Notably, the puzzle given to solvers is able to be solved, albeit to RED HERRING, and knowing how to solve it in that state is important for solving it in the 'original' state.
• Peaches (Galactic Puzzle Hunt 2019) - After playing through the game, solvers are told that there's a way to get a 'secret ingredient' to the phrase GORGEOUS CAKE in only 9 steps (and using each transformation once). Assuming that the secret ingredient is the final answer, solvers then have to work backwards to figure out the only phrase that can accomplish this.
• Guidebook (Puzzle Potluck 4) - In this puzzle, solvers are presented with the solution to a puzzle that doesn't exist on the hunt website. Based on the information in it (which refuses to go into specific detail), solvers need to reconstruct the original puzzle (a 6x6 grid of words).

See Also

• Puzzles involving Retrograde Solving