Cells R9C5, R9C7, R9C8, and R9C9 can only contain the candidates 3, 5, 6, or 8. Since column 9 already has 3, 5, and 6, cell R9C9 can only be 8.

@@slyhzsudoku I see, makes sense. Thank you

At 00:19, the 8 is in B2, C2, not B1, C2. Consequently, I had to take the necessary action.

@@slyhzsudoku Yes there is already an 8 in B1, C2 at R2, C5. But the 8 in B1 has to be at either R1, C2 or R3, C2. That blocks the 8 in B4 from R5, C2. That along with the placement of the 1, 2, and 6 in B4 all in C1 at R4-6, C1 means that R5, C2 can only be a 5. The puzzle goes from seemingly impossible to easy after the placement of the 5. I don't think I've ever seen this happen to such an extreme degree before.

@@johnmiller5629 Yes, you are correct. The presence of the 8 in B2, C2 necessitates the existence of 8 in B1, C2. Consequently, R5, C2 can only be a 5. I didn't have to go through so much hassle. Thank you for pointing that out.

@@slyhzsudoku Sadly, I found that at more like the 19 minute mark and not the 19 second mark. I was just about to give and start with the pencil marks.

@@johnmiller5629 You're quite humorous! The video itself is just about 6 minutes in duration. I'm curious, how did you manage to pinpoint something at the 19-minute mark? Thank you for taking the time to watch my video. Your comments have actually inspired me to create a Sudoku video for December 19th, which wasn't initially on my agenda.

I think I may have just been confused because if r5c7 is a 6, clearly r5c8 couldn't be 4... but that's outside the logic of the XY wing ruling our 4 from r6... so really only one version of the XY wing even works because of the way the pair in box 5 interacts with the XY wing. So I really needed to ignore the 4/6 in cell r5c4.

Yes, you should ignore the 4/6 in cell r5c4. The XY wing is formed by cells r6c5, r5c7, and r5c8. Since both r6c5 and r5c8 contain the candidate 4, and the bottom row of box 6 intersects with these two cells, it rules out the possibility of 4 in the bottom row.

Glad you like them!

❤​@@slyhzsudoku

Thank you for commenting on my video. I edited out the time I took thinking so people wouldn't get impatient when they watched my videos. Normally, it takes me 20 minutes to an hour to finish a puzzle like this.

Thanks for watching.

Thanks for watching.

I have been asking the same question in my mind.

Thanks for watching.

Which cell do you refer to?

Thanks.

Granted, sound does make the video easier to follow. I will take your advice into consideration. The reasons I use different marks to explain my video instead of sound are: firstly, it is easier for me to edit it into a short video; secondly, there is no language barrier.

@@slyhzsudoku Your videos are VERY EASY to follow! Keep up the good work!❤

@@robertgalebach6227 Thanks.

Thanks for watching!

Thanks for watching!

Thank you for watching and commenting on my videos. Actually, it took me more than 8 minutes to solve the puzzle, then it took me about 2 hours to edit it into an 8 minute or so video so people could understand it better.

Thanks for the visit