挑戦状 (chousenjou) Japanese meaning: written challenge | KotomoraHe sent a written challenge to his rival.
Usage patterns
〈人〉に挑戦状を送るto send someone a written challenge
He sent his rival a written challenge.
挑戦状を突きつけるto throw down the gauntlet (boldly present a challenge)
The rookie team threw down the gauntlet to the champions.
挑戦状を受け取るto receive a written challenge
She received a mysterious challenge letter.