Gimmel Nissan, 5774
A young bochur in eighteenth-century Italy once undertook a vow to abstain from playing games of any kind. He later approached the rabbis of his community and asked them to annul the vow, claiming that he could not recall if he had actually stated the vow verbally. He also wanted to know if a differentiation could be made between chess and other types of games.
The issue was brought to Rabbi Shimshon Murfurgo of Ancona, after which no less than seven other Italian Rabbis were asked to state their opinion on the matter. Rabbi Murfurgo cited the ruling in Shulchan Aruch (Yoreh Dei'ah 228:15) that a vow not to play games may not be annulled. The reason for this is because it is forbidden to annul a vow if doing so may lead to the performing of a transgression, and it is forbidden to play a game that involves gambling (see Shulchan Aruch Choshen Mishpat 34:16).
A possible solution would be to only allow the young man to engage in games where no gambling is involved, while his vow would still be in effect with regard to gambling. The problem with doing this is that once part of a vow is annulled, the entire vow is automatically absolved as well (see Shulchan Aruch Yoreh Dei'ah 229:1). Hence, allowing him to play games without money would, in effect, open up the possibility for him to gamble as well.
Perhaps one could argue that the vow had not taken effect to begin with, because a vow is only binding when stated verbally (see ibid., 210:1). However, being that the man was uncertain whether he had expressed the vow in speech or not, we must be concerned that the vow is indeed binding, because sefeika de'oraysa lechumra (if one's not sure of the circumstances, (s)he should take the stricter point of view).
However, Rabbi Murfurgo concluded that a differentiation can be made between chess and other games. Chess involves wisdom and skill and is not a complete waste of time; we can therefore assume that he had not included it in his vow.
A number of other rabbis disagreed with Rabbi Murfurgo's differentiation, as they maintained that chess was undoubtedly included in the vow. The fact that the witnesses had seen him playing chess and did not rebuke him serves as no proof to the contrary; perhaps they hadn't been paying attention, or they hadn't wanted to hurt his feelings. "The young man should take to heart," wrote Rabbi Gavriel Pontrimoli, "that 'all is in the hands of G-d except the fear of Heaven.' He must place more effort in controlling his yetzer!"
(Shu"t Shemesh Tzedakah, Yoreh Dei'ah §32. Pachad Yitzchak, Os Shin, Erech Shevuah Shelo Lischok)