BeginnerExercise136/Solution

Solution ( at )  

White first plays throw-in and . If Black defends the right, White takes the left ko first. And...

Solution ( at )  

If Black defends the left with , White starts another throw-in ko in the right and use the left ko capture as a ko threat. This is a kind of double ko and Black can't fight the left ko using outside ko threats because White can always use the other ko capture as a ko threat - so is forced. Then effectively takes the right ko first.

Tactically inferior  

here makes throw-ins at and miai to start a ko. This is tactically inferior because Black takes the ko first. On the other hand, this may work as a strategic probe: White asks "Which side do you defend?" and chooses strategy depending on Black's answer, keeping the option of starting a ko later.

Clearly worse ( at )  

The other throw-in first is a mistake. This is even worse than the diagram above in two respects: 1) Black has 1 extra point (prisoner), and 2) Black can resolve the ko by capturing at a.