Intuitive Corner Recognition

Technically this is the first thing that I ever developed. In early 2006, soon after I started using the Roux method, I was trying to figure out how to recognize CMLL. Gilles Roux's site only provided a table of cases with arrows showing which corners need to be swapped. There were no patterns or any detailed recognition guide. So I thought of a way to recognize the corners based on knowing the correct sticker order around the cube when solved. Checking the sticker order of the corners upon reaching CMLL reveals the swap that needs to be performed.

After using this for a short time I felt that it was too slow and that there must be a better way. In an email to Gilles about the issue, he pointed me toward the Waterman style recognition of looking at four stickers and comparing the matching, adjacent, and opposite relationships. More specifically, he linked to Lars Vandenbergh's COLL page. I then switched to this, but that initial idea that I had was only the start of my thinking about corner recognition. Eventually I completed Gilles' original NMCMLL recognition, developed an improved version of that, then ATCRM, and then Straughan. Actually, I revisited this initial recognition idea in 2024 thinking that there must be more to it. That is what led to me discovering the minimum sticker recognition seen in the Straughan recognition concept.

First, memorize the sticker order that should be around the sides of your preferred LL color. Using the standard color scheme and yellow as the upper layer, the sticker order starting from the R layer and going clockwise should be Red Red Blue Blue Orange Orange Green Green. Then, follow these steps:

1. Check the U face sticker orientation. You can also do this after the following steps. Either way works.

2. Find two matching stickers on two adjacent corners.

3. Check the other non-U sticker of one of the two corners. Two stickers are now known from this corner.

4. Move to the corner adjacent to the corner that had two stickers checked and look at its color that would be considered matching or opposite of the sticker from step 3. For example, if in step 2 you locate the two red stickers on two adjacent corners, and in step 3 the sticker is blue, then in this step look at the blue or green sticker of the third corner.

There are advancements available to make the steps not as strict above, but the steps presented are to provide a simple explanation.

Each of these patterns are completely intuitive and not based on memorization.

• In the all permuted Sune case example, the sticker order matches exactly that of the solved cube.

• In the left swap Sune case, the two corners on the right have the correct order, but then the third corner is out of place, showing that the left two corners need to be swapped.

• In the diagonal swap Sune case, the right two corners aren't in the correct order and we know those two need swapped to have the yellow red blue corner at UFR. The corner that should then be at UFL should be the other blue corner, but instead it's the other green corner. So both the left and right sides should be swapped, which is equivalent to a diagonal swap.