The Ultimate Pro achievement description reads as
Reached maximum proficiency with your first weapon.
Which weapon should actually be counted as first? Is it the straight sword you get in the prison during the prologue mission? Or is it the first weapon of your choice that you obtain in Japan?
Best Answer
Based on the discussion here, it looks like the trophy is poorly worded. It seems that the unlock is actually from maxing out your first weapon type, which is at 999999/999999. You can actually choose any weapon type for this; it doesn't have to be the one you started with. By "first", it means the first one you max, not the first one you pick up.
This is also supported in PowerPyx's trophy guide: