Working through a puzzle

Okay, rather than take each step and show you pictures, this time I'm going to just show you what the puzzle looks like at various stages of solving, and point out some things that happen along the way.

Thinking track, top left

 In this section notice that square MC has a triplet left, consisting of twoshares tl(4/8), tc(4/9) and br(8/9).

Thinking track, top right

This corner has a twin, the (2/4) twoshares in TRr.  They aren't pairs in a square or a column, but if you've marked twoshares they show up whether you worked the rows across or just column Rr.  And naturally, they'll eliminate the other 2s and 4s in TR and Rr.

 Underneath columns Ml and Mc, you'll see I've encased the remaining unassigned symbols in a square.  That's a shorthand I use to say, "I've gone as far as I can here until something forces a change."

thinking track bottom right

And of course, if something resolves itself so quickly that I don't need to write in the digits, I just put a square.

Zipper

With hard puzzles, I sometimes find myself at a point where I can't squeeze out any more information without bifurcating.  I think of it as "trousering" and of my bifurcation point as the "zipper".  I could pick a twoshare (and often do), but I wanted to take advantage of the triplet in MC, so I chose to zip the pair of 4s in that square, and noted with an arrow pointing to the 4 in the thinking track notation for MC.  The circle and the triangle tell me how each chain goes from here.

I'll talk about the consequences of that next time, because I'm tired now, and I can't find the pictures I want.