The Pillar of Honor is located on Sentinel's Peak north of Wanderer's Bluff.
The Mongol Fortress may be blocking the entrance to this location. But you will be able to avoid it and also fight if you don't want to. It has a few shamans throughout the area, and the benefits they offer to opponents when you see them are quite a bit for our skill level.
You will also be able to climb a cliff wall in the back in the fortress leading to the Pillar of Honor, which has the sword kit.
After reading this article on where to find the Immortal Hope Sword Kit in Ghost of Tsushima, we hope you get through all the steps and find the Sword Kit for your enjoyment.