What is the ruling on one who broke his fast on an unknown number of days in Ramadan by intentionally emitting semen, thinking that this does not invalidate the fast or necessitate expiation, knowing that this was the first Ramadan he had fasted, and is expiation obligatory for these days whose number he does not know?

Masturbation during daylight hours in Ramadan (definition) invalidates the fast, and the days on which masturbation occurred must be made up. Expiation (kaffarah (definition)) is not obligatory, as there is no evidence to necessitate it. It is recommended to increase in seeking forgiveness (istighfar), performing good deeds, avoiding provocations, hastening marriage or increasing in fasting, and adhering to righteous company.