min:825 max:1019 diff:194 range: 800 - 1050 step:2.5 800 825 850 875 900 925 950 975 1000 1025 1050 +---------+---------+---------+---------+---------+---------+---------+---------+---------+---------+ I---------------------I 在原業平, 0825 - 0880 ?-------------------------------I 紀貫之, 0866? - 0945 I--? 古今和歌集, 0905 - 0914? ? 土佐日記, 0934? - 0934? ?------------------? 紫式部, 0970? - 1019? ?--? 源氏物語, 1001? - 1008?