Abstract: A chair, comprising: a seat portion and a back portion, the back portion comprising: a front surface and a rear surface, a channel with an opening that extends in a length direction of the back portion on the front surface, and an accessory holder system, comprising: a rail that extends in the length direction of the back portion, an accessory holder disposed in the channel and slidably mounted on the rail, the accessory holder configured to hold a support accessory in position on the front surface, and a securing mechanism to releasably secure the accessory holder at different positions along the rail.