Kyobashi Market is best treated as a timing-dependent stop rather than a static sight. Come when vendors are active and the place is doing what it is meant to do: selling, chatting, feeding regulars, and giving Okayama a bit of everyday texture. Its location makes it easy to combine with a walk through the surrounding part of Okayama.
Morning is usually the safest bet for markets, though individual schedules vary. Bring cash, move slowly, and look for what locals are buying before deciding where to spend your appetite or curiosity.