Inscribed on the walls at Karnak: In Year-23 on IX.19 Thutmoses III and the Egyptian army arrived at Megiddo.
“… Year-23, 1st Month of the third season, day 21, the day of the feast of the true new moon. Appearance of the king at dawn.”
The Egyptian vanguard appears to have arrived on the I Shemu 19 after passing through the narrow pass to the rear of Megiddo, perhaps this was in sufficient strength to deter an attack by the Canaanite enemy, the vanguard then awaited arrival of the rearguard on I Shemu 20 before launching their own assault. Despite Thutmoses’ order of I Shemu 19 to prepare for battle the next day the Canaanite forces may have avoided battle on I Shemu 20. Thus, I Shemu 21 might actually be correct.
Thutmoses Year-23 is 60 years after Amenhotep Year-9.