Rubik's Cube: How to Look Ahead (F2L) — Transcript

Full transcript

1. 0:00Look ahead means as you solve one thing, (e.g. F2L Pair)
2. 0:02you're looking ahead to other things that you're going to solve next so that you don't have to pause in between.
3. 0:07Look Ahead is incredibly important as it can be the difference between someone who averages 12 seconds and someone who averages 6 seconds.
4. 0:13But it's not so straightforward,
5. 0:14because there are many times when you solve something and you can't see anything else you're about to do, because of this look ahead is
6. 0:20Not just a thing
7. 0:20You know about and start doing, it's something you have to actively practice and get very good at so before Look Ahead will actually become
8. 0:26useful to you here are some things you have to be able to do first
9. 0:29So if you have a pair like this,
10. 0:31One of the steps of F2L is to make sure that they're both in the top layer.
11. 0:34But this isn't the best way to do it because with Advanced F2L, which is shown in this video (refer to top right of your screen),
12. 0:38you have to be able to get them into the top layer while pairing them up at the same time like this so that you
13. 0:42Can insert it right away. You also have to do special cases like this
14. 0:45efficiently and also know how to do them into the back slot to avoid rotations
15. 0:49those are just some of the things covered in the Advanced F2L video and you have to be at least decent at all of
16. 0:54them to be able to move on next anytime. You see two pieces from an F2L pair
17. 0:57You have to be able to instantly know how to insert this into the correct slot in my Advanced F2L video,
18. 1:02I told you how to compare stickers here to learn how to pair these up like that
19. 1:06But that's just the first step, eventually you want to have practiced these all so much that once you see these two,
20. 1:11you know instantly how you're going to insert it into the back and the pairing step is just part of the process
21. 1:17That you have all in your muscle memory.
22. 1:19so in other words anytime you see an F2L Pair, you have to be able to do it quickly and
23. 1:23Without looking because if you had to look at it,
24. 1:26That means you're not really familiar with what you have to do in order to solve it,
25. 1:29so to test if you're at this level yet, every time you see an F2L pair just close your eyes and then do it as
26. 1:34fast as you can with the fastest turns that you can possibly do and
27. 1:38Then so that there it is and then just stop, look at the cube, and then do the next one as fast as you can
28. 1:45So if you can always do all of those then you're definitely ready for Look Ahead.
29. 1:48And if you can do those chances, are you currently averaged between 15 and 25 seconds.
30. 1:52You may average over 25 and still find all of those to be true for you because you happen to turn slower than other people
31. 1:58And that's totally fine. Just make sure you're honest with whether or not you can do those things
32. 2:01Otherwise look ahead won't really be useful to you at all. And you should keep working on those now
33. 2:05We'll talk about the MOST important thing about look ahead, this phrase, "Slow down, and look ahead,"
34. 2:09Has been very popular in the speedcubing community and it really boils down to two
35. 2:13Important things obviously slow down and look ahead
36. 2:16But that creates two new questions,
37. 2:17Which is "How slow should I go?"
38. 2:19and
39. 2:19"How exactly do I look ahead?" So the look ahead part means to look away from the pair that you are currently solving, because you
40. 2:25Should be so good at solving these pairs that you don't need to look at them to solve them although by now
41. 2:29It's probably an ingrained habit to look at this while you solve it
42. 2:31But we are going to try and get rid of that habit.
43. 2:34So I'm going to try and look at other pairs while I solve this. And for now,
44. 2:37We're just going to fixate on a corner
45. 2:39So here I'm going to start pairing them up and I'm gonna look at this corner. So just watch the white sticker of it and
46. 2:46Watch how I'm going very slow as I do that and we see it ends up here not very hard to track if I go
47. 2:50That slow and now for the same pair. I want you to watch the edge that went with that
48. 2:56So again not very hard to track if you're just watching the edge
49. 2:59The hard part is going to be finding the corner and edge and tracking them both at the same time.
50. 3:03Which seems like a very big task to ask for when you used to just look at the current pair you were solving. The more
51. 3:09Experience you have the more you'll just be able to
52. 3:12Visualize in your head preemptively how approximately they're going to move which sounds like I'm not really telling you anything,
53. 3:18but because there are so many different possible F2L cases interacting with each other
54. 3:22It takes a lot of time to develop the intuition needed to see how these pieces move.
55. 3:26You shouldn't really flowchart how pieces move very often
56. 3:29You should just get a feeling of how they move by doing a lot of experience
57. 3:33So now is when practice is SUPER SUPER important.
58. 3:35So now for slow down and look ahead we know what it means
59. 3:38But we don't know exactly how slow to go and where exactly we should look so first
60. 3:42I'll answer the question of "How slow you should go?"
61. 3:44There are two answers to this and it depends on what your goal is, if you're working on look ahead as an exercise
62. 3:49Then you want to go as slow as you need to go for it to still be challenging to not pause
63. 3:54So, for example, I'm solving this one
64. 3:56If I go with this slow
65. 3:58It is very easy for me to think very hard about how I'm gonna do these as I'm doing those and now I see this
66. 4:04So, this is
67. 4:06Probably too slow for me right now based on my level of skill for look ahead
68. 4:10And in the beginning this may actually still be too fast for you because you're not used to all the places
69. 4:15You're supposed to look so in the beginning. This is a totally fine speed to go at just for practice.
70. 4:19But if you find that it's not challenging for you anymore,
71. 4:22Then there's no point and you should speed it up a little bit to improve your look ahead skill under more realistic fast turning conditions
72. 4:27So if you regularly been doing slow turning look-ahead
73. 4:29exercises and you now just want to go for fast resolves because it's good practice or you have a competition coming soon then you just
74. 4:35Want to slow down a little bit and a little bit is very vague, but here's an example the fastest
75. 4:39I would normally be able to solve this is something like that then you probably now want to turn out about this speed
76. 4:44notice how in these two the speed is not that different but the movements of the pieces is
77. 4:48Far easier to track in the one where it went slightly slower. This will vary depending on your level of look ahead
78. 4:54So you may have to go slower or you may even be able to go faster than this depending on how good you are
79. 4:58at look ahead but if you can look ahead while almost going at your regular turn speed this video probably isn't for you. (No seriously, why th are you watching this? - Subtitle Guy)
80. 5:03So now let's discuss the second part of this and where do we look ahead to,
81. 5:07Often just slowing down to find pieces isn't enough because you don't know where to look and sometimes the spots you look are not the
82. 5:13spots where pieces are going to be and this gets very
83. 5:15advanced when it comes to deducing where pieces are or memorizing things
84. 5:18But here I'm just going to get you started with a very simple concept
85. 5:21so first of all,
86. 5:21There's a factor of what's easier to find corners or edges and the answer is probably going to be corners because they have
87. 5:27White or your cross color on them, and those are easier to spot.
88. 5:30So I'm gonna start solving this and then just watch this white corner right here and we're gonna find out what color is on it
89. 5:35And then where it finally ends up.
90. 5:39So there it is and if you're watching more than just the white corner
91. 5:42You would have realized that its corresponding edge was right here.
92. 5:45Although that can be hard to find if you're not used to this.
93. 5:47So anytime you solve a slot and you find a corner in the top layer,
94. 5:51Hopefully there may not be any in the top layer which is a bad case.
95. 5:54But we're just gonna assume for now,
96. 5:55There always will be one.
97. 5:56Chances are its corresponding edge will also be somewhere in the top layer because there are four slots
98. 6:01It can be in the top layer while only four spots
99. 6:04It can be in the middle layer, but you would have solved a slot
100. 6:06so
101. 6:07Chances are it's in the top layer, and if it's in the top layer all the 'U' moves you just did earlier from solving this
102. 6:12pair should have made it not very hard to spot as you did those moves and then you can just go and solve this pair
103. 6:17Afterwards, so that was the simple case. They were all in the top layers
104. 6:20So now I'm gonna solve the same one. The corner same corner is right here and
105. 6:25This time I don't see is corresponding edge anywhere.
106. 6:27And so if it's not in the top layer, it's got to be in one of these slots
107. 6:29So that's where you're gonna look next,
108. 6:31The front slot is very easy to see because you can see both of its colors.
109. 6:34But the back slots are a little harder to see in this case. This one is yellow,
110. 6:37So it's obviously not the one that goes with this.
111. 6:38So it must be that one but that can take a while to deduce and that is quite advanced.
112. 6:42So, how can you make this easier on yourself?
113. 6:44Let's say we got the same case say, from over here before we started doing it
114. 6:48then in this case we would have to rotate to here or
115. 6:54to here
116. 6:55The best way to rotate is so that we're inserting this into a back slot.
117. 6:59Because when we insert it into the back slot we have the same corner here now
118. 7:02But it's edge could be anywhere in the top layer, of course or it can be any of these two front slots
119. 7:08and if it's not there then
120. 7:09Finally, we look at the back slot and there's only one spot remaining
121. 7:12so look-ahead can be immensely easier if you just
122. 7:15Solve back slots earlier rather than later and if you have to solve back slots, then you never have to look there again.
123. 7:20So once you find the corner, you know
124. 7:22It's edge has to be either in the top layer or the front two slots
125. 7:25And that makes looking for it far easier.
126. 7:27Now I'm not saying that when you get this case you should do a y2
127. 7:30Rotation because that's slower,
128. 7:31if you get it from my case where you do have to rotate such as you're facing this way or you're facing this way and
129. 7:36You do have to rotate to solve it then you should rotate so that it's going into a back slot now
130. 7:40Of course, there are times when you can find an edge before you find its corner and that's totally fine.
131. 7:44You don't have to find the corner first.
132. 7:45I'm just showing this particular method of look ahead as one way you can get started and it is very effective, now
133. 7:51Here's the crossed understand example F2L with emphasis on all the things that I talked about.
134. 7:55So here I have these two [corresponding edge and corner] and I'm going to pair them like that and then insert it into which way should I rotate?
135. 8:02back slot and
136. 8:03then this one and this one [corresponding edge and corner] and I'm going to
137. 8:07Rotate so I'm inserting into a back slot as I do that
138. 8:10I'm just going to take note of what I have here. I have this one in this one [corresponding edge and corner]
139. 8:12So I'm going to watch where those move and then go into this one [F2L Pair] next and inserting it again into a back slot
140. 8:19So any time I have to rotate just do back slot only if I have to rotate, I'm not going to do unnecessary rotations.
141. 8:25And then these two [corresponding edge and corner]
142. 8:27So now a quick review of what we talked about look ahead is very important
143. 8:30But only if you are already pretty good at doing your F2L solutions
144. 8:34Efficiently and without much thinking. Once you can do that,
145. 8:37You want to slow down and look ahead.
146. 8:38Slowing down either means going slow enough that you don't have to pause (just as an exercise) or
147. 8:42Going just a little slower than your regular turn speed (if you're still trying to get fast times)
148. 8:47You should generally do a mix of this practice,
149. 8:49Don't just pick one over the other, and then for where to look try to find corners first because they will be easier
150. 8:54find, you don't have to do it this way
151. 8:55But this is just one method that you can stick to that is very reliable.
152. 8:58After you find the corner look for its edge which can either be in the top layer or in any of the slots.
153. 9:02So you want to insert into back slots more often (whenever you have to choose y or y' rotations)
154. 9:05So that you don't have to look into those back slots to find your edge.
155. 9:08And again, this is not always going to work and you don't always have to do this,
156. 9:11But it's a very reliable technique that will help to get you started.
157. 9:14And once you start practicing look ahead, and you want to start getting some new ideas or optimizing the things you're doing then check out
158. 9:19my Advanced F2L playlist in the description
159. 9:21Look Ahead is a very big concept and I have a bunch of videos that are
160. 9:25Specific to certain parts about Look Ahead. For example, how to take advantage of memorizing where certain pieces are, how to track piece movement better,
161. 9:31How to practice better, and so on. So thanks for watching. I hope you learned a lot and I'll see you guys next time
162. 9:35*J Perm hitting the Stackmat Gen 4 Timer*
163. 9:36*J Perm scrambling*
164. 9:40Subtitles by: TeslaCuber / EpicBig CSI