Maybe it's because of the trading routes, that games got created. Parts were assembled or created from different games to be traded in a city like the city of Lothal. That idea could make the origins of chess date back to over 4000 years.
en.wikipedia.org/wiki/LothalSince many things have been pasted down from word of mouth, I would imagine chess started from Southeast Asia. During the The Vedic Sanskrit times (1500 – 600 BCE)
en.wikipedia.org/wiki/SanskritThe Ashtapada predates chess. So we have a starting date when chess could have been created or built from other games as a variant. An idea or game always comes from something else. The imagination helps creates things.
en.wikipedia.org/wiki/Ashtapadaen.wikipedia.org/wiki/Chaturanga"Chess in the Indian epic poetry" (Press view detailed to read more. Press the numbers to reach the original link)
www.perplexity.ai/?s=u&uuid=8be57a48-1bae-4067-8050-cae3870162df"Duel between two Indian princes." Sounds like the two sides of the chess pieces.
Shatranj goes back before 760 AD because the pieces already existed back then.
sites.google.com/site/caroluschess/antique-chess-setsI think, Chess probably originated from a tribe like Kuru and was played in the fields. The chessboard could represent the Kuru territory. From the fields it went into trade centers and go traded to others places in the world.
So when did the first chess set appear in your city or store?
I guess once the AI's have read every thing and dated things in chronical order, it will be able to say the main line of the origines of chess and maybe even the first city it appeared in. If they can trace the cities it appeared in they will find the origins of the city from where the idea came from or the variant it came from.