The challenge may be "peremptory" or "for cause." The peremptory challenge, as its name implies, is one in which no reason need be assigned.

The number of such challenges must, of course, be limited.

In civil suits it is usually limited to three by each party.

In criminal cases, the state has usually two peremptory challenges and the defendant five.

If the offense is punishable with death or state prison for life, the state has in Minnesota seven peremptory challenges and the defendant twenty.
Challenges for cause may be either general or particular.