In fact, the Chinese character 咫 (reads as ata) seen in Nihonshoki (Chronicles of Japan) was replaced with 尺 (reads as "shaku") in Kojiki (The Records of Ancient Matters), which is exemplified by Yata no kagami (八咫鏡) replaced with 八尺鏡.
実際、日本書紀では「咫」と書いているものを、古事記では「尺」の字で書いているもの（八尺鏡など）がある。