A canon must undergo a historical process of elimination and selection. Lin Ku-fang has specified that the most recently a song can have appeared is 30 years ago; that is, of contemporary music, he collects and records only those that are more that 30 years old in order to avoid being too subjective due to overly close proximity in time. Such works have undergone selection by at least one generation of people.
經典必得經過歷史的淘汰及篩選，林谷芳將樂曲編輯的最後年限定位為三十年，也就是說當代的樂曲他只收錄三十年以前出現過、經過一世代人篩選過的，以免因為時間的距離太近，而過於主觀。