semelis: The difference between
a: the correct sequence
and
b: descending to E1 after B2-B3 exchange
c: descending immediately at E1
is the size of the threat that playing at E1 makes. Or how big of a sente move it is.
D1, also wrong, would reduce black territory by 1 more point why also protecting 2 points in white's side but in gote.
So D1 is a 3 points in gote move. E1 (with or without preparations) is a 2 points sente move ~ 4 points gote move, so better.
For those wondering.
The difference between a: the correct sequence and b: descending to E1 after B2-B3 exchange c: descending immediately at E1 is the size of the threat that playing at E1 makes. Or how big of a sente move it is. D1, also wrong, would reduce black territory by 1 more point why also protecting 2 points in white's side but in gote. So D1 is a 3 points in gote move. E1 (with or without preparations) is a 2 points sente move ~ 4 points gote move, so better. For those wondering.