Gokyo Shumyo, Section 4, Problem 28 / Solution

Solution  

The key move in this problem is the clamp at .

Solution  

If captures the three Black stones, then and captures the five White stones in a connect-and-die.

Solution  

It is possible for White to resist through a ko-fight, but this ko is extremely unfavourable for White (a picnic ko) as (i) Black takes first; (ii) White has to fight a two-stage ko; (iii) Black has a ko-threat at a; and (iv) this ko is very heavy for White as White is betting the entire corner.