Japan expels contests (6)

I believe the answer is:

jousts

I'm a little stuck... Click here to teach me more about this clue!

'contests' is the definition.
The definition and answer can be both related to natural events as well as being plural nouns.
Maybe they are linked in a way I don't understand?

'japan expels' is the wordplay.
'japan' becomes 'j'.
'expels' becomes 'ousts' ('oust' can be a synonym of 'expel').
'j'+'ousts'='JOUSTS'

Can you help me to learn more?

(Another definition for jousts that I've seen is " contests on horseback".)

I've seen this clue in The Guardian.

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