Original sentence: The six Waka poets derived from the anthology of poems Kokin Wakashu (905), where Ki no Tsurayuki, one of compilers, referred to them as "famous poets in the near past" in the preface.The six most well known Waka poets (六歌仙 Rokkasen) were selected poets of Waka in the early Heian period
Edited sentence: The six best Waka poets (六歌仙 Rokkasen) were selected poets of Waka in the early Heian period.The six best Waka poets derived from the anthology of poems Kokin Wakashu (905), where Ki no Tsurayuki, one of compilers, referred to them as "famous poets in the near past" in the preface