Seasons
A grain's child will grow with the seasons. In spring the grain is born, it grows in summer, is harvested in fall, and dies in winter.
き
None
None
All of the seasons have their own special key (き). As they change, that season's key appears and unlocks the next step in the grain's life.
An update is needed before you can continue but you have more than one WaniKani tab open.
Finish up what ever you are doing on the other tab(s), then close them to continue.
The update will complete automatically once the other tab(s) are closed.