Device including plurality of markers

A device comprising:

• a case body including:
• a grasping portion to be grasped by a user's hand;
• a curved portion;
• and
• a plurality of operating members configured to be operated by the user,
• wherein:
• the curved portion includes a plurality of markers configured to emit light to an outside of the case body, and
• the light emitted from the plurality of markers is to be received by an image sensing device of a head-mounted display to determine a relative position of the device.

A system including:

• a device including
• a case body including:
• a grasping portion to be grasped by a user's hand;
• and
• a curved portion;
• and
• a head-mounted display including an image sensing device,
• wherein:
• the curved portion includes a plurality of markers configured to emit light to an outside of the case body, and
• the head-mounted display captures, via the image sensing device, the light emitted from the plurality of markers to determine a relative position of the device.