On this daf, we find some halachos of mourning.
One rov in Yerushalayim heard of various ways of understanding when to be lenient regarding these complex halachos. Some said that if there is a dispute, one should always rule leniently. Others claimed that citizens of Yerushalayim should always follow the rulings of the Gesher Hachaim, since this was the custom in Yerushalayim.
He decided to present his questions to Rav Yosef Shalom Elyashiv: “When a person has a situation in aveilus regarding which there is a lenient opinion and a stringent one, which way should he rule?”
Rav Elyashiv replied that there is no easy way to know: “Every question requires adjudication by a competent authority who is aware of all the factors. For example, you need to know the custom, since minhag plays a disproportionably large role in determining these halachos.”
“Is it correct to say that the custom of Yerushalayim always follows the rulings of the Gesher Hachaim?”
“No. In every instance you need to know whether the custom actually followed his opinion.”
Rav Elyashiv offered one final word of guidance: “There is an important rule regarding the customs brought in the Matzeivas Moshe by the Chayei Adam. These customs are authoritative and should be followed” (Ashrei Ha’ish, Yoreh Deiah, Part II, p. 324-325).