To find a way through the market without raising the alarm in The Broken Blacksmith in the Ghost of Tsushima jump down the right side of the house and assassinate the guard.

Go behind the boat and through the tall grass towards the other side of the market. Go through the middle of the carts in the market and keep going into the house ahead.

Assassinate the guard in the house and exit it through the flap at the back of the house.