The Ishango Bone is similar to the Bilzingsleben Bone which my research indicates is a Solstice Calendar. Early man recorded the direction of the rising Sun on the horizon every two weeks as it moved from solstice to solstice. The solstice calendar divides the year into 26 two-week periods. The names for each of these 14-day periods survive in the Chinese calendar describing the weather at that time. Dividing the year in this fashion may be the clue to deciphering Stonehenge where the Aubrey holes marked both the rising and the setting Sun. Both of these bones belong to the same family of artifacts with engraved lines.