Philip Marshall (or Phil Marshall) was a resident of Port Ludlow, Washington State, USA. In 1998 at around the age of 72, he published "The Ultimate Solution to Rubik's Cube" on the Internet. Intended for beginners, he referred to it as "a unique solution using only two series". It only requires 65 moves to solve a scrambled Rubik's Cube, although it is not well suited for advanced speedsolving.
Marshall's solution is an Edges First solution. Although he never uses these terms, his method involves positioning and orienting the edges with a [1,1] commutator, and then positioning and orienting the corners with a pure [[1:1],1] commutator, using conjugation when necessary. He referred to his algorithms as an "Edge Piece Series" and a "Corner Piece Series". In standard notation, these are U'RUR' and URU'L'UR'U'L (together with reverse, mirror versions, etc.).
The solution steps are:
- Make a cross.
- Solve 3 of the 4 middle-layer edges using the "Edge Piece Series".
- With the same Series solve the top face edges (automatically solving the last middle-layer edge).
- Use the "Corner Piece Series" to solve the top 4 corners.
- Use the same Series to solve 1 of the last 4 corners, then use conjugation (if necessary) and the same Series again to solve the last 3 corners in one go.
- Only two algorithms (and two mirror equivalents) need to be learned
- Low move count compared with most other beginner methods
- Solvers gain some understanding on how the Cube works, rather than treating it as a "black box" to which algorithms are applied
- Method can be used to solve many other twisty puzzles
- Not the easiest method for beginners to learn, and the final step can be hard to grasp
- A relatively slow method because a lot of time is spent inspecting the Cube
- The method is interesting but cannot really be called "ultimate"
Although intended for beginners, Marshall's guide was difficult to understand, although he did offer a 53-minute videotape for sale. Marshall's webpage also provided solutions for the 2x2x2, 4x4x4, and 5x5x5 cubes. His webpage has stayed available for a long time because puzzle-enthusiast Georges Helm mirrored it on his website. It also gained fame because User:rline  (from TwistyPuzzles.com Forum) created an influential blog. His website "Twisty Puzzling", which existed between 2011 and 2017, contained a clear explanation of the method, together with numerous video tutorials.
- The Ultimate Solution to Rubik's Cube, the Mirror on Georges Helm's website
- Explanation of the Philip Marshall method, 18 minute video by Greg's Puzzles, April 2017
- The Ultimate Solution to Rubik's Cube, 1999 snapshot of Marshall's website, at the Internet Archive
- Twisty Puzzling Blog, 2016 snapshot at the Internet Archive