Commentators often divide sumo into eras, each defined by its outstanding rivalry.
Whether it's Akebono vs. Takanohana, Taiho against Kashiwado or Tochinoshiki taking on Wakanohana, great yokozuna pairings have traditionally been the standard way to separate one generation of rikishi from the next.
So dominant has Hakuho been over the past 13 years though, it's fair to wonder whether any rival will be mentioned in the same breath by future writers.