Dropping back problem 1 / Solution

White connects in sente  

forces to save the corner (White can get a ko to kill it). Then White plays tenuki here.

Dropping back  

The point being that and are sente plays now, but don't break through, an example of dropping back. Nothing difficult, with in place; but you have to see it in a real game to feel the force of it.

Going back to the start  

Assuming this came about as a result of the play here, is required. After , can White take still take sente?

Going back to the start (continued)  

This is much more profitable for Black (next Black a and White will have to take the stones); so that in practice White may not be able to take, should play reverse sente.

Going right back to the start  

The way the problem was set makes this / exchange first look better.

Charles Matthews