User blog comment:Plexioth- xD/Monster Hunter 3 Ultimate/@comment-4452412-20121004212915/@comment-3062343-20121004220846

HR1-HR2 is low rank, HR3-HR5 is high rank. Guran Miraosu is the urgent to go from HR7 to HR8, at which point the HR system changes to Tri's style, and all quests you've completed previously go towards increasing your HR. Since I spend a fair amount of time trying to get Heavenly Scales/Shells, I went straight from HR7 to HR60-something when I beat Guran. Oh, and the last quest is unlocked at HR100, so that's when Hunter Rank stops really mattering.