Sudoku Puzzles

Lovely photo, Vici!

1)Start at 22,SSTS to UP=28
2)(4)e9=h9-h5=(4-3)i5=(3-8)f5=(8-9)f8=f2-f1=(9-2)b1=(2-1)b3=(1)e3,=>e3<>4.UP=81

Thanks Anne - it was a wonderful walk out to this ledge. How I loved visiting the Grampians!

14:25

1. Basic techniques to UP = 28
2.(2=5)f3 - (5=36)c36 - (6=92)b15 => b3, de1 <> 2; UP =81

UP=28
xy-chain
(9)b1=(6)b5=(3)c6=(5)c3=(2)f3 => de1<>2 UP=81

1. Unique possibilities to 28.
2. If b1=9=c7,b5=6,c6=3=a3,a2=4=e3;12 have no place in column b.So b1=2.UP81.

Hi rwm. After your 36 at c36, this does not yet eliminate 6 from b5, does it ?
Regards, Alfred.

maen all! no one past the barrier fence please!

18:07

my take on this rather easy one: SST=>28
(6)b2=b5-(6=3)c6-(235=1)bcf3 => b2<>1; UP=81

or Alfred's way, if b2=1,b5=6, by inspection b3=1 so b2<>1

Alfred: in rwm's chain, (36)c36 is weak with (6)b5.
(2=5)f3-(5=3)c3-(3=6)c6-(6)b5=NP(29)b15. is a simpler way to write it.

simpler yet:
f3=2 OR f3=5 and by inspection NP(29)b15.

sotir's solution w/o all that egregious and confusing documentation:
e9=4 OR h9=4 and by simple inspection e3=1, so e3<>4.

Alfred: even after filling in your 8 or so Ups, I still have a place for 12 in column b -> b2=1, b3=2. Did I miss some simple 'inspection'?

OK - add c3=5, f3=2 AND b3=2 to Alfreds solution.
as a chain -unclear why you threw in c7=9, a2=4 and e3=4:
(2=9)b1-(9=6)b5-(6=3)c6-(3=5)c3-(5=2)f3 => b3<>2
your chain would be much longer if I padded it with c7,a2,e3.

-looks a lot like Bud's XY-chain.

farpointer, by inspection, 1 is locked at de2 (after e3=4). What I meant yesterday by "inspection" is simply making use of locked candidates, and other SSTs. This is much simpler than following a long AIC chain. Maybe for a computer it is equivalent, but not for a human.
Thanks for explaining rwm's solution.

..or even easier - if you look very closely this is actually UP to 81, no chains or anything else required.

SE=7.3