Solving a 2x2, though might look easier, if one needs to be fast in it, definitely requires some level of knowledge on how to solve a 3x3 Rubik’s cube as well.
This is the exact reason why advanced methods in 2x2, namely CLL, EG1 and EG2 (Collectively called Full EG), require the cuber to know around 120 algorithms, a lot of which might be familiar from the knowledge of solving a 3x3. These advanced methods can be broadly divided into 2 steps, the base layer and 1 algorithm for the top layer. This is the reason why 2x2 solves are extremely fast when compared to other puzzles like 3x3, pyraminx, etc.
Most of the solves of advanced 2x2 cube solvers are sub 2 secs or even sub 1.5 secs! This type of speed can only mean one thing, no pauses. After completion of the base layer, they directly start with the algorithm for the top layer, sometimes even with some cancellations while making the first layer. So, the question here is, how are these speedcubers able to solve a 2x2 without any pauses right from the start by using Full EG? The answer is One-Look.
What Is One-look?
One-Look is a technique used by many speedcubers, wherein they are able to predict what case they will get on the top layer, by tracking the movements to build the base layer. In theory, if a person can one-look as many moves as he can, he does not need to look at the cube, rather can solve the 2x2 blindfolded, while having the exact same timings! This is the reason why one-look is very much popular among many of the top cubers, as it can be extended to other puzzles as well. Once, one-look is mastered, there will be a significant drop in the times for 2x2.
How To Practice One-look?
Though the concept sounds a bit difficult, with practice, one-look can be mastered by anyone. To start off, we need to analyse the change in position for each and every piece, when there is an R rotation. This starting point is really crucial, and really understanding this, will make the further steps much easier. It is crucial to analyse for the other single movements as well, like R’, L, L’, U, U’, F, F’, etc.
Once this is properly understood, the next step would be to analyse the change in position for each and every piece, when there is a U R’ rotation. This might be a little bit more tricky as there are multiple pieces involved when performing 2 moves. This needs to be done for all the possible 2 move combinations, like U L, U2 R, F R, F’ R, etc. One can also try to set the base layer to be solvable with 2 moves, and try to predict what case might end up on the top.
Follow-up For One-look:
Once 2 move cases are mastered, then one proceeds to increase the moves one by one, like 3 moves, 4 moves, and to make it really difficult, 5 moves as well! The complexity of the cases is exponential as we increase the number of moves. Advanced cubers can one-look up to 5-7 moves at a time, and this gives them an almost 100% chance they will be able to one-look every single time.
While practising the above exercises, one can, in parallel, slowly try to incorporate one-look into their solves. This might take up all of your inspection time, but that is okay. Once properly mastered, one-look generally takes not more than 5-8 secs to predict the solution.
One-look is the single most essential part of 2x2 speedcubing, without which reaching the sub 2 barrier is very difficult (Unless really lucky!). If anyone is looking to seriously get into advanced 2x2, then apart from learning CLL, EG1 and EG2, one must definitely start training in one-look to really improve their times.