Whetstone of Sharpening

Wondrous item, rare

It is said that only one with courage could sharpen his blade with this whetstone with cowards finding only dull iron.

During a short rest, you may use this whetstone to sharpen a bladed weapon. If you enter combat before your next long rest, you must spend every action and movement with the intent of attacking your opponents in combat with the sharpened weapon.

If you do, you gain +1 on attack and damage rolls and include a roll of 19 as a critical hit. If you do not, or if you spend a turn out of combat, you instead have disadvantage on your next attack.