I actually found this one surprisingly approachable, so I highly recommend trying it yourself before watching the solution in the video. Not the solution, just a small hint to get started Think...

I actually found this one surprisingly approachable, so I highly recommend trying it yourself before watching the solution in the video.

Not the solution, just a small hint to get started

Think about the given total, all the cells in the diagonal lines, and the possible values for them.

The only real "secret" you need to know to solve it is that adding 1-9 = 45, and 45 x 9 = 405.

Reporting in, after 20 minutes of math: Relatively detailed spoilers The clues tally up a total of 58 cells (counting doubles double). That's an average of just over 3 in those cells, so very low....

Reporting in, after 20 minutes of math:

Relatively detailed spoilers
The clues tally up a total of 58 cells (counting doubles double). That's an average of just over 3 in those cells, so very low. I'm gathering that the counted cells are low and the non-counted are high.

I've computed a relatively naive restriction of 177 vs the 178 by doing the per-block minimums that count towards the 178. Every cell that is touched by a / and a \ counts twice. I'm one short of 178. That means one of two things: I've done the math wrong and it's actually 178 vs 178, which means I would know a bunch of numbers. Or the minimum assignment I assumed is actually subtly not quite possible somehow and it gets forced up to 178 that way.

Curiously, I haven't made much use of 405 and 45 "secrets", and I think I'm past the point where they could become useful. Care to share how you made use of that? I think my method might be a bit on the brute-force side of things.

Spoilers It's not 177. You're right that you should actually be able to place at least one digit right away, and quite a few other very tightly constrained possibilities. And the puzzle is really...

Spoilers

It's not 177. You're right that you should actually be able to place at least one digit right away, and quite a few other very tightly constrained possibilities. And the puzzle is really straightforward sudoku after that.

As for the "secret", it's not used per se, so maybe I shouldn't have mentioned it or worded it that way. I mentioned it more just to get people thinking about summing cell totals in a similar manner, although as you figured out it has to do with the lines, with the overlaps being double counted, and going from there.

I'm pretty sure you actually can figure out the constraints of the non-line cells using 405-178, but that there would be a few degrees more freedom doing it that way, leaving you with a larger spread to then have to whittle down afterwards.

I changed my hint. Hopefully it's more helpful now, but still doesn't totally give it away.

Turns out, the sum of 1 through to 2 isn't in fact 2, it's 3. That helps. Though the puzzle was just as plausible as a puzzle with a slack of one that you could somehow eliminate.

Turns out, the sum of 1 through to 2 isn't in fact 2, it's 3. That helps.

Though the puzzle was just as plausible as a puzzle with a slack of one that you could somehow eliminate.

I actually found this one surprisingly approachable, so I highly recommend trying it yourself before watching the solution in the video.

## Not the solution, just a small hint to get started

Think about the given total, all the cells in the diagonal lines, and the possible values for them.

~~The only real "secret" you need to know to solve it is that adding 1-9 = 45, and 45 x 9 = 405.~~Reporting in, after 20 minutes of math:

## Relatively detailed spoilers

The clues tally up a total of 58 cells (counting doubles double). That's an average of just over 3 in those cells, so very low. I'm gathering that the counted cells are low and the non-counted are high.I've computed a relatively naive restriction of 177 vs the 178 by doing the per-block minimums that count towards the 178. Every cell that is touched by a / and a \ counts twice. I'm

oneshort of 178. That means one of two things: I've done the math wrong and it's actually 178 vs 178, which means I would know a bunch of numbers. Or the minimum assignment I assumed is actually subtly not quite possible somehow and it gets forced up to 178 that way.Curiously, I haven't made much use of 405 and 45 "secrets", and I think I'm past the point where they could become useful. Care to share how you made use of that? I think my method might be a bit on the brute-force side of things.

## Spoilers

It's not 177. You're right that you should actually be able to place at least one digit right away, and quite a few other very tightly constrained possibilities. And the puzzle is really straightforward sudoku after that.

As for the "secret", it's not used per se, so maybe I shouldn't have mentioned it or worded it that way. I mentioned it more just to get people thinking about summing cell totals in a similar manner, although as you figured out it has to do with the lines, with the overlaps being double counted, and going from there.

I'm pretty sure you actually can figure out the constraints of the non-line cells using 405-178, but that there would be a few degrees more freedom doing it that way, leaving you with a larger spread to then have to whittle down afterwards.

I changed my hint. Hopefully it's more helpful now, but still doesn't totally give it away.

Turns out, the sum of 1 through to 2 isn't in fact 2, it's 3. That helps.

Though the puzzle was just as plausible as a puzzle with a slack of one that you could somehow eliminate.