Way of the Kensei.

Monks of the Way of the Kensei train relentlessly with their weapons, to the point that the weapon becomes like an extension of the body. Founded on a mastery of sword fighting, the tradition has expanded to include many different weapons.
A kensei sees a weapon much in the same way a calligrapher or a painter regards a pen or brush. Whatever the weapon, the kensei views it as a tool used to express the beauty and precision of the martial arts. That such mastery makes a kensei a peerless warrior is but a side effect of intense devotion, practice, and study.

Level 3 Features:

Path of the Kensei.

When you choose this tradition at 3rd level, your special martial arts training leads you to master the use of certain weapons. This path also includes instruction in the deft strokes of calligraphy or painting. You gain the following benefits:
Kensei Weapon Arts.
You gain proficiency with martial weapons, and any martial weapon that lacks the special or heavy properties becomes a monk weapon for you, as well as the glaive and longbow. These weapons lose the heavy property when you use them as monk weapons. When a monk feature would require an unarmed strike, you can substitute a melee weapon attack, but the weapon's normal damage die is replaced by your Martial Arts die.
Agile Parry.
When you are hit with an attack while holding a monk weapon that lacks the reach trait, you can use your reaction to gain a bonus to your Armor Class against the triggering attack, potentially turning it into a miss. The bonus equals your proficiency bonus.
Kensei Shot.
You can use a bonus action on your turn to make your ranged attacks with a monk weapon more deadly. When you do so, any target you hit with a ranged attack using a monk weapon takes extra damage equal to your Martial Arts die. You retain this benefit until the end of the current turn.
Way of the Brush.
You gain proficiency with your choice of calligrapher's supplies or painter's supplies.

Level 6 Feature:

Ki-Empowered Weapons.

At 6th level, you extend your ki into your monk weapons. Your attacks with your monk weapons count as magical for the purpose of overcoming resistance and immunity to nonmagical attacks and damage.

One With the Blade.

At 6th level, you gain the following benefits:
Deft Strike.
When you hit a target with a monk weapon, you can spend up to 3 ki points to cause the weapon to deal extra damage to the target. The bonus is equal to your Martial Arts die times the ki points spent. You can use this feature only once on each of your turns.
Stunning Shot.
You can use your Stunning Strike feature when you make a ranged weapon attack with a monk weapon, for the cost of 1 additional ki point. You cannot make use of both benefits on the same turn.

Level 11 Feature:

Sharpen the Blade.

At 11th level, you gain the ability to augment your weapons further with your ki. As a bonus action, you can expend up to 3 ki points to grant one monk weapon you touch a bonus to attack and damage rolls when you attack with it. The bonus equals the number of ki points you spent. If the weapon was already a magic weapon with a bonus to attack and damage rolls, you cannot increase the total bonus beyond +3. This bonus lasts for 1 minute or until you use this feature again.

Level 17 Feature:

Unerring Accuracy.

At 17th level, your mastery of weapons grants you extraordinary accuracy. If you miss with an attack roll using a monk weapon on your turn, you can reroll it. You can use this feature only once on each of your turns.