Chess on Shabbat is technically allowed but many note it would be better for adults to spend the day in Torah learning.
See for instance R Gil Student
You would be wrong to take for granted the permissibility of playing
chess on Shabbos. The issues raised include: making sounds, conducting
business, non-Shabbos behavior.
Apparently, on old chess boards, metal pieces that knocked into each
other made musical sounds which might be considered forbidden on
Shabbos. However, Shiltei Ha-Giborim (Rif, Eruvin 35b nos. 2-3)
permits this because the players do not intend to make music with
these sounds. The Rema (Shulchan Arukh, Orach Chaim 338:5) follows the
Shiltei Ha-Giborim. Note that the Magen Avraham (ad loc., no. 8)
confirms that the Rema is discussing chess (but requires using a
special Shabbos set).
The Magen Avraham quotes from a R. A. Sasson who argues that playing
chess is similar to conducting business. He seems to mean that because
chess was often played for money, even when you omit the prize the
game is still forbidden because of its usual practice. However, the
Rema rules that chess is only forbidden when you play for money.
Many argue that chess is simply not appropriate for Shabbos. For
example, the Shemiras Shabbos Ke-Hilkhasah (16:34) dismisses all
arguments to forbid chess. However, earlier in the chapter (16:1), he
says that this only applies to children. Adults should spend the day
in spiritual–religious–pleasure. Similarly, R. Moshe Feinstein
(Iggeros Moshe, Yoreh De’ah 3:15:2) rules that chess is not
technically forbidden but should be avoided because of ve-dabeir
davar, by which I think he means that the game is not in the spirit of
Shabbos.
See here from R Eliezer Melamed
Poskim disagree whether one may play games on Shabbat. Some say that
since Shabbat is meant for Torah study, one may not play games, as
that would be wasting time that could be used to study Torah.
Accordingly, one may not play checkers, chess, backgammon, billiards,
or any ball game, whether the games are played inside on the floor or
outside on a paved area. And since one may not play these games, they
are considered muktzeh as well (R. Aharon Sasson, cited in Birkei
Yosef 338:1; Petaĥ Ha-devir ad loc. 4).
Others maintain that there is no prohibition on playing games on
Shabbat, as long as nobody is playing for money (Rema 338:5; Ma’amar
Mordechai). Indeed, some rabbis would play chess on Shabbat, as it is
a game that requires thought and sharpens the mind (Shiltei
Giborim).
In practice, it is appropriate for adults to be stringent and not play
ball games, chess, and the like, both because it is prohibited
according to some poskim and because one should not to get used to
neglecting Torah study on Shabbat. Those who wish to be lenient have
an opinion on which to rely (see SA 308:45; MA 338:5; MB ad loc. 21;
Kaf Ha-ĥayim ad loc. 39). Children should also be trained to study
Torah on Shabbat, but almost all poskim agree that one should not
prevent them from playing games on Shabbat