resolve the ko

ko  

Black has played a ko-threat to which White decides not to respond :

Connection  

connects and thereby resolves the ko, in short white connects the ko. (In Japanese, this shape is called 'Umebachi'; name of a flower-shaped Japanese heraldry)

2. Capture

ko  

If the marked stone is present, White can resolve the ko in a different way.

Capture  

It is now more profitable to capture the marked black stone to end the ko. This shows fundamental efficiency of ko; White has ignored atari and secured one point of territory and a likely eye at a by not connecting.