Hm, interesting.
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- Click Here To Show Diagram Code
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I don't think

is a natural extension because it has no connection to White's corner stone. If at 'a', I could see the connection (pincering an approach move by Black) but then it would be a lukewarm extension not really countering Black's wide Shimari. I guess, you can even make a point that with such a wide Shimari the extension loses value because you have considerable less strength to back it up - though, that's probably above my head (or wrong?) ; )
For me, this just denies Black a good extension but the prospects for a good White development look slim - meaning, this move has no good follow-up in my opinion. If White takes his Shimari then

ends on the wrong side. If White plays something like Keima from the 3-4-stone, then there is a lot of room for Black to enter.
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- Click Here To Show Diagram Code
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If we imagine that play goes like this, then I guess I erred on saying the top and the left are Miai since now the right side seems more important for both. Now

is a natural extension, countering Black's Shimari. But after this I find it quite complicated to say which moves are now biggest. 'a' or 'b'? And what about the bottom?