Regarding chess Ayatollah Sistani’s ruling is clear as to it is being haram without question regardless of gambling. Though i would like to know of the hikmah (wisdom) behind it and as to which elements of chess make it haram per say. As in the current times chess is not related to gambling and is mostly seen as a brain exercise and a competitive sport. Therefore, the confusion as to what leads to such a sport having such severe consequences as mentioned in hadith, though I could not find a hadith relating its elements which cause it to be as such.

Sayyid Sistani’s opinion regarding chess is that if playing with it is not more gambling in all countries, and it has become a mental game, then it is permissible to play with it, otherwise, it is not permissible.
The reason for that is the narrations that came with the prohibition of gambling games.