Ryoko's Guide to the Yokai Realms, pg 219
The tutelage of a hanataka tengu, or countless hours of careful study of hanataka treatise on combat, has granted you the following benefits:
• Increase your Dexterity or Wisdom score by 1, to a maximum of 20.
• You gain proficiency with one Finesse weapon of your choice.
• As a reaction when a creature misses you with a melee attack while you are holding a Finesse weapon, you can make one weapon attack with that weapon against the creature. You can use this benefit a number of times equal to your proficiency bonus, and you regain all expended uses when you finish a long rest.