Developers Suckerpunch has been open about the influence of the cinematic work of the great Akira Kurosawa on the Ghost of Tsushima. They have gone to great lengths to make the game look as good as possible, not just graphically, but by resisting any kind on intrusive HUD. Things like waypoints are replaced with gusts of wind, and all nonessential information fades from the screen when it is not needed.
To take it one step further, they have included a special mode called Kurosawa Mode, known as Samurai Cinema Mode during development, that will give the game the classic look of a Kurosawa film, changing it to black and white with a slightly textured film effect. This is not a throw away mode. Bad conversions to black and white can make an image lose a lot of detail, and can make screen difficult to read, but this mode works extremely well, and you can play through the entire game this way if you wish.
You will actually be asked if you want to activate this mode from the very start of the game, so if you hit yes and want to turn it off, the instructions are the same.
To activate the mode, hit the Options button, then go to the Display tab. Scroll down to the Kurosawa Mode option and activate it or deactivate as you wish. The mode will also work with the game inbuilt camera mode, allowing you to take some stunning screenshots of the game that Suckerpunch have created.