Puzzle #5

This is a Total Masyu puzzle, a variant of Masyu. In addition to the rules of Masyu, all possible circles have been given; i.e. it is not possible to add any more circles to the grid so that it is consistent with the solution.

Difficulty: hard

Theme: Clue minimalism and logic.

Puz-PRE link. (Note: While a valid solution to this puzzle will be marked as correct, Puz-PRE does not have the "total" constraint programmed in. The solver may incorrectly mark incorrect answers as correct.)

This is one of the most stunning puzzles I've ever made, I think. The break-in is almost completely original (in that I came up with it and then found that it was already used by someone else, like two other break-ins I've "discovered"). While this puzzle still isn't MellowMelon-difficulty (it'll take a long while before I get there!), and it doesn't require excessive trial and error, it's definitely not a Total Masyu for the uninitiated.

EDIT: Twitter user @That_Scar has asked the following question:

@edderiofer Am I stupid or is this pretty easy? [SOLUTION IMAGE REDACTED]

— ThatScar (@That_Scar) September 16, 2016

To this, I respond that I don't consider a logic puzzle to be solved unless one has proven uniqueness of solution. Finding a solution may be easy, but proving that it's unique is the hard part.

Rules of Masyu

Draw a single loop through the centres of some cells according to the following rules:

1. The loop may only travel horizontally or vertically, never diagonally; all turns are right-angled turns. The loop may only turn at the centers of grid cells. The loop may not cross itself or branch off; that is, from any cell centre, there can be only 0 or 2 loop segments extending from it.
2. The loop must pass through every circle.
3. The loop may not turn at a white circle, but must turn at at least one of the adjacent cells in the loop.
4. The loop must turn at a black circle, but may not turn at either of the adjacent cells in the loop.

Below is an example and its answer.