You've trained your whole life mastering specific weapons which you use to to peak ability 

Favored Weapons

You've spent your life mastering your skills with select Polearm's, You are proficient with the Sword Staff, Spear, QuarterStaff  and Double Bladed Scimitar
Additionally, you gain features while wielding one of these that also act as your monk weapon.

Flowing precision

At 6th level, you extend your ki into your favored weapons, granting you the following benefits.

your spell save DC = (8 + Prof + Wisdom mod)

Magic Weapons. Your attacks with your favored weapons count as magical for the purpose of overcoming resistance and immunity to nonmagical attacks and damage.

Serpents Tail. When you hit a target with a weapon weapon, you can spend 1 ki point to trip your enemy, the target must succeed a dexterity saving throw against your DC, on a fail they fall prone. This does not work against creatures immune to prone or creatures more than one size larger. 

Scorpion Strike. When you hit a target with a weapon weapon, you can spend 1 ki point to attempt to push the target back 10 feet. Target must succeed a strength save against your DC or be pushed away from you to feet.

Spiders web.  When a creature misses you with a melee attack roll, you can spend 1 ki point as a reaction to redirect that attack to hit one creature of your choice, other than the attacker, that you can see within 5 feet of you.

Piranha Strike

When you reach 6th level in this class, once per turn, when you hit with a favored weapon you may deal additional damage equal to your martial arts die. 

Leaf in the wind

At 11th level, you gain the ability to augment your abilities further with your ki. As a bonus action, you can expend 4 ki points to grant a bonus to your AC. This bonus lasts for 1 minute or until you use this feature again. In addition you do not provoke opportunity attacks from any creature you hit until the end of your turn. 

Lightening strikes twice

once per turn, If you critically hit with an attack using a favored weapon you may spend 1 ki point to make an additional attack against the same creature. 

Vipers Dance

At 17th level, your mastery of weapons allows you to fall into the rhythm of combat. Consecutive hits on a target increases the damage they take from you. 

Whenever you score consecutive attacks against a target, increase the damage die dealt by 1D8 for each hit after the first. if an attack misses the accumulated die returns to 0

Additionally when you take the attack action on your turn, you can make three attacks