The Chessu were a warp-capable species from the Delta Quadrant. They resided in a region of space also occupied by the Antarians, the Aksani, the Terrellian, the Imhotep, and others.

Two Chessu ships participated in the Antarian Trans-stellar Rally of 2377. Ambassador O'Zaal had promised the hosting of the post-race ceremony to the Chessu, which caused protests by the Aksani. (VOY: "Drive")

This species was only mentioned in dialogue.
According to Star Trek: Star Charts (p. 94), there was a star system named Chessu, which might possibly be the system of origin for this species, in the quadrant. The primary of this system was a F-class star.
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