Roux (French pronunciation: [ʁu]) is a Rubik's cube speedsolving method invented by Gilles Roux. Roux is based on Blockbuilding and Corners First methods. It is notable for its low movecount, lack of rotations, heavy use of M moves in the last step, and adaptability to One-Handed Solving.
1. Build a 1x2x3 Block anywhere on the cube.
2. Build a second 1x2x3 block opposite of the first 1x2x3 block, without disrupting the first 1x2x3 block. After this step, there should be two 1x2x3 blocks: one on the lower left side, and one lower right side, leaving the U slice and M slice free to move.
Steps 1 and 2 are referred to as the First Two Blocks
4a. Orient the 6 remaining edges using only M and U moves (UF, UB, UL, UR, DF, DB need to be oriented correctly).
4b. Solve the UL and UR edges, preserving edge orientation. After this step, both the left and right side layers should be complete.
4c. Solve the centers and edges in the M slice, see Last Six Edges.
Steps 3 and 4 are referred to as the Last 10 Pieces
- Like the Petrus method, the Roux method uses fewer moves than the popular Fridrich method.
- It is also more intuitive and requires fewer algorithms.
- After the first block is built the rest of the cube can be solved mostly with R, r, M and U moves thus eliminating rotations.
- CMLL is one of the best algorithm sets as there are only 42 cases and most algorithms are fast OLLCPs from CFOP
- The blockbuilding and intuitive nature of the method allows for rapid improvements in lookahead and inspection
- The LSE step of Roux is very easy to master, as it has easy lookahead and allows for fast, 2-gen MU TPS.
- Block building can be difficult for a beginner to get used to. The reliance on r and M moves may also be difficult for some people, so much so that cubers who have trouble with M turns should probably not use this as their main method (or better, practice the M moves).
- Since the M-slice is used often, especially in the final stages, there is a larger chance of a DNF rather than a +2 if the solver misses the second flick in an M2, or if the solver misses the last M move. It is a DNF because M uses both the R and L face in one.
- The M-slice becomes increasingly difficult with higher order puzzles. With 7x7x7 and 6x6x6, many argue that Roux is essentially unusable; however, with practice, one may be able to do well with it on big cubes.
- The M-slice is very difficult with OH, and OH Roux solvers almost always need to utilize table abuse and therefore can pretty much never solve one-handed away from a table or other surface. However, if one practices doing one-handed M-slices, it can be done very well but only with a table (which shouldn't be a concern in competitions).
Free/Non-Linear Blocks: The first block and second block do not need to be built in that order. You can build part of one and finish the other later. This is very useful when there are a lot of free, pre-built blocks and pairs.
Non-Matching Centers: The first two blocks can be built around incorrect centers. This allows for more efficiency and allows Roux users to take advantage of pre-built blocks. The centers can be corrected directly before CMLL with either u M' u' or u' M' u.
CMLLEO: Some Roux users have learned multiple algorithms for each CMLL case, each affecting edges in a different way. This allows for manipulation of edge orientation, leading to an easier LSE. CMLL + EO was an idea originally being developed by Thom Barlow under the name KCLL. Soon after, Thom Barlow suggested changing the name to CLLEO.
Non-Matching Blocks: Another improvement is to expand to solving any of the four possible second blocks. This means that the D-layer colors of the two blocks don't have to match. After building non-matching blocks, the fastest way to recognize CMLL is through the use of the NMCLL recognition method. If a new Roux solver plans to use non-matching blocks, it may be best to learn this method for recognizing corners. Otherwise, corner recognition will be difficult if the choice is made to use a different recognition method. There is a complete guide to using non-matching blocks at this link.
Pinkie Pie: A variant proposed by Alex Lau in 2016, it involves orienting the UL/UR edges on the D layer while using an OLLCP algorithm to orient the remaining edges and solving the remaining corners. The user then will get a 4a skip and a very easy 4b step. While this may seem good, many faster Rouxers are of the opinion that it is simply better to influence the EO step and not go to all the hassle of placing UL/UR on D and having to recognise an OLLCP. There is also the reason that many Roux solvers use the method to have less algorithms and do not want to learn the huge OLLCP algset.
EOLR: A variant proposed by Gilles Roux and first developed by James Straughan. It was also fully documented by Iuri Grangeiro with some assistance from Kian Mansour. Iuri Grangeiro was the first person to use a lot of EOLR in competition. EOLR gained popularity after being shown in YouTube videos produced by Kian Mansour and has since become a common technique for Roux users to learn. EOLR combines steps 4a and 4b of the method, orienting edges and placing the UL+UR edges simultaneously. In the EOLRa variant, the UL+UR edges are placed on the D layer and in the EOLRb variant, the UL+UR edges are solved. The cases are all intuitive and can be learned without memorizing them as algorithms.
UFUB: Instead of solving ULUR edges in 4B, UFUB are solved. This can lead to more efficient solutions, but lookahead becomes much more difficult. It is most useful for skipping the "dots" 4C case, but requires center recognition and more lookahead.
Misoriented Centres: Standard roux involves orienting all 6 edges relative to the center colour that is on the bottom of the blocks. Instead, we can orient them relative to the front colour. As with UFUB, efficiency is improved, but lookahead is hindered. This is most useful for known EOLR cases.
ACMLL: The left and right blocks can be built with flipped pairs, swapped pairs, pairs from the opposite side block, and even misoriented or swapped individual pieces. The blocks can then be corrected during CMLL. This significantly reduces the move-count of the blocks and allows the solver to plan more during inspection. There is also flexibility in allowing the solver to learn new F2B arrangements and the associated ACMLL algorithms.
- See also: Advanced techniques for Roux
Roux on other puzzles
There are lots of different methods for a variety of different puzzles inspired by Roux. A selection of the most known methods and their respective puzzles is listed here:
- 4x4x4 (and other Big cubes): Meyer method, Kenneth's Big Cubes Method, Stadler method, Lewis Method, CR4, BigRoux
- Square-1: LBL (Square-1) (cubeshape, two corner-edge-corner blocks, D edges, PLL), Lin, Screw
- Skewb: Skrouxb Method
Most notable here are the Square-1 methods, because they are the second most popular behind Vandenbergh and since one of them has been used to set a world record.
- Gilles Roux
- Thom Barlow (Kirjava) 
- Austin Moore (BigGreen) 
- Jules Manalang (Waffo) 
- Alexander Lau (5BLD) 
- Kaijun Lin (林恺俊) 
- Mitsuki Gunji
- Artur Kristof (Arcio) 
- Kian Mansour 
- Kavin Tangtartharakul (GuRoux) 
- Vincent Wong (Kangaroux) 
- Sean Patrick Villanueva 
- James Straughan (Athefre)
- Original Method Proposal
- r/rouxcubing subreddit
- Roux help and discussion thread
- One-question answer thread
- Waffle's Roux Tutorial
- Gilles Roux's tutorial
- Kian's Roux Guide
- Beginner's Roux video tutorial
- Tutorial in French
- RubiX Cube Solver - Roux Method Tutorial app
- Reading Roux corners tables
- James Straughan's Non-Matching Blocks Speedsolving Method
- Roux step 4b-4c transition help
- Kian's Youtube Channel
- Waffle's Roux Site
- Wikia: Roux Method
- 5BLD's and PandaCuber's Roux Tutorial