The Time Thief explained v2

This is an enhanced version of a previous explanation:

https://www.chess.com/clubs/forum/view/the-time-thief-explained

The Time Thief moves like a Queen.

The Time Thief can be captured by other pieces. But the Time Thief itself cannot capture other pieces in a normal way.

However, the Time Thief has a special way of postponed capture:
If an enemy piece is in reach of the Time Thief, and does a move, the Time Thief can as response revert the entire move and then capture the piece.

In this diagram, the black Rook is in reach of the white Time Thief. Suppose Black plays Rf2.

As response, the white Time Thief can revert Black's previous move. So it would move the black Rook back from f2 to f7. And then it can capture the black Rook on f7. As a result this would be the position:

The Time Thief must do this capture on the very next turn, or the right to do so is lost!

The Time Thief cannot revert a move after being captured itself:

After Rxh3, the Time Thief is off the board, and has no powers to revert that move and capture the Rook.

If the Time Thief reverts a move, it reverts all aspects and everything what happened with that move. It really turns back time.

In this diagram, Black might play Rxi7. The Time Thief can revert that move and capture the Rook on f7, but that also means that the Queen comes back on the board on i7 : the Queen is restored by the Time Thief.
After Rxi7 TTxf7:

In the following diagram, Black has just played pawn f7-f5:

Before f7-f5 was played, the Rook was in reach of the Time Thief. but the Rook did not make any move. So the Time Thief cannot capture the Rook.
The pawn did move, but did not come from a square in reach of the Time Thief. So the Time Thief can also not capture the pawn.

In the following diagram, the White King is in check.

White might consider to play ixj7, thinking that his King is indirectly protected by the restoring powers of the allied Time Thief. This is not allowed. A Time Thief cannot restore his own allied King. In this position, White must get out of check.

A King in reach of an enemy Time Thief, is not yet in check.

White to move here. With any move by the White King, White would put himself in check, because it allows that the black Time Thief will capture the white King. This position would be Stalemate, as White has clearly no legal moves left.

Note that in the same position with black to move, Ke4+ would be an illegal move for Black. Although the White King seems to be frozen by the Black Time Thief, he still gives check, if the Black King would approach to an adjacent square.

Fairy piece interactions

Time Thief and Spirit

Scenario: a possessed piece is in reach of a Time Thief and the Spirit leaves that piece.

Additional rule 1: If the Time Thief is unpossessed then the lone Spirit is invulnerable for the Time Thief. The Time Thief can't take.

Additional rule 2: If the Time Thief is possessed then the Time Thief can capture the Spirit. The piece that was possessed by the Spirit will as a consequence also be captured. This is a circumstantial double capture and is allowed. If the possessed piece was a Dwarf then the circumstantial double capture is still allowed whether or not the possessed Time Thief had an allied co-attacker.

Other scenario's with Spirit and Time Thief are already covered by the existent rules.

Rules for King restoration

Here, a set of rules is given where the Time Thief is so powerful that he can restore the allied King.

In the basic set of rules, a Time Thief cannot restore the allied King. In this advanced set of rules, a Time Thief can in fact restore an allied King.

If a player has a Time Thief in his army, then the FIDE laws for check, mate and stalemate do not apply to this player. It is legal for this player to expose the own King to an attack.
This player loses the game, when his King is captured, and he fails to restore his King with his Time Thief on the very next move. This player even loses the game, when he answers with capturing the opponent's King instead of restoring his own King.

For a player without a Time Thief: getting out of check must be done before capturing the opponent's King.

A player with a Time Thief survives and can play on, as long as he is able to restore his King immediately after losing his King.

As soon as a player loses his Time Thief and still has his King (*), then the FIDE laws for check, mate and stalemate immediately apply to this player.

(*)"... and still has his King" has been added, as to anticipate that people combine the advanced Time Thief rules with other pieces that have double capture abilities.

Examples

White to move: ixj7 is a legal move. Nxe1 is answered with TTxf3 and White still lives.

White to move: ixj7 is a legal move. But not a good move. After Nxe1, TTxf3 is possible, but then after Bxe1 White cannot restore his King and loses.

Black to move: Black has no Time Thief in his army. He must get out of check, and Nxe1 is not a legal move for Black.

White to move here. Let's assume that White plays jxi8. TTxj7 is the only move for Black, or else Black loses. Black might be tempted to play Nxe1 instead, but that loses instantly. After losing his King, Black must restore his King on the very next move.

White to move: White is in big trouble and whatever move he can do is losing.
Let's see:
1. Ne3 Rxi1 with mate, as White's Time Thief is captured and FIDE rules apply to White now, and it's badly mate.
1. Ng1 Bxj1 King cannot be restored and white loses.
1. Kxj2 Rxj2 King cannot be restored and white loses.
1. TTg1 Qxj1 King cannot be restored and white loses.

In previous position, it was Black to move, and Black decided to take the Knight on d1.
Again, no matter what White does, he'll lose the King and - with that - the game.

Now in this diagram:

If it was White to move: stalemate.

If it was Black to move: Ke4# is legal for Black and wins.

Players with the Time Thief can choose to play with or without this advanced set of rules with King Restoration, as long as they discuss and agree upfront.

Only the OG bulldog players remember the arguments of Conditional Check...

But the arguments are there. Combined with the FIDE rule that the King can't be taken, I've come into a logical labyrinth.

In a game where stalemate does not exist, and the King can and must be taken to win, there it is feasible to define such a Time Thief. Chu Shogi is such a game.

The King can't be taken! I think on the last diagram Ke4+ must be an illegal move!

That's exactly what I said there 

Rule clarification

"If an enemy piece is in reach of the Time Thief, and does a move, the Time Thief can as response revert the entire move and then capture the piece."

In this position, Black plays i7-i5. Because the Time Thief sees the pawn on i7, TTxi7 is allowed. There have been remarks that i7 is blocked for the Time Thief by the same pawn. But that is irrelevant. Whether the Time Thief sees square i7 or not, is to be judged before black moves the pawn.

I modified the 2nd post and in that gave rules for an advanced Time Thief that can restore the own King.

Let’s say in a K and TT vs K, if a king is frozen by the TT, does that mean stalemate or a win on the next move?

With the lone King to move stalemate.

Something must be wrong with possession of a time thief voiding all FIDE laws pertinent to stalemate. All is fine as concerns check and mate, since those are singular concrete ideas. But stalemate is more tricky. The rules for "advanced" time thief as hereinabove written work when dealing with your king moving to attacked squares. But stalemate (as defined by FIDE laws) can still occur simply as result of getting your king surrounded by friendly pieces, none of which can move. If such a situation is not ruled a stalemate, is it then a loss for the "stalemated" player, who then must lose on time?

P.S. This type of stalemate is possible in chu shogi, although it would take gross incompetence to reach. To stalemate yourself in chu shogi would require such a powerful position to even go so far as to advance multiple connected pawns to get unpromoted, which requires completely destroying the opponent's lance + reverse chariot. In fact, stalemating yourself in chu shogi is so difficult and requires such strength that I would not be opposed to having it ruled as a winning condition for the player with no legal moves.

@dax00, if you are in the posession of a Time Thief, you cannot be stalemated. The description said: "It is legal for this player to expose the own King to an attack." That means, in the advanced set of rules: do your move, then lose your King, and then hope that your Time Thief is in the position to restore your King. The advanced set of rules is consistent and clear.

@evert823 No, you misunderstand. I mean your king literally cannot move. All squares around the king are covered by friendly pieces. You of course can't take your own pieces. And none of those pieces have moves.

I think I get your point. Before answering that let's see if we can construct such a position. I doubt if that is even possible 

With king in the corner and weak pieces, it's definitely possible. One simple solution is to give a player with an "advanced" time thief the ability to pass their turn. Or just call that version of stalemate a draw.

White to move here. OK, current advanced rules have no outcome in this position. White has no move and stalemate does not exist. I'll fix the rules for this when this actually occurs in a game. Till then I am totally fine with having this as a gap in my rules.

I am more concerned with another gap in my advanced rules. So far, we haven't seen the combination of an advanced Time Thief, and a piece that can capture two pieces in one turn, e.g. a chu Shogi Lion. But what if we start a game with such a combination? Now what happens if such a piece captures my (advanced) Time Thief as well as my King in one turn?
I lose my Time Thief, so the FIDE laws of check, mate and stalemate immediately apply to me. But then I am without King, while the FIDE laws don't allow that.

People who intend to start a game with such a combination can announce this to me, and then I will be happy to make a decision about this. (Are you interested dax00?)

Using the same principle from chu shogi that a lion's double-move should be considered each step separately...

• If a lion captures the time thief first, the enemy king would already have lost. Capture the time thief, do not capture the king, declare victory.
• If a lion begins on a square covered by the time thief, and it captures the enemy king on a square not covered by the time thief, it may finish its move on another square. The time thief is unable to revert the move. Thus, the lion can usually avoid the time thief's ability.
• If a lion begins on a square covered by the time thief, and it captures the king on a square not covered by the time thief, then if the lion either terminates its move or returns to the square on which its move began, the time thief may then revert the move. This is because moving back to its original square is considered a stationary capture.
• If a lion begins on a square covered by the time thief, and it captures the king on a square covered by the time thief, the time thief can revert the move, capturing the lion.

From the perspective of the Time Thief and the FIDE laws, we should consider the entire move/turn only. The Lion used his one turn to do one move consisting of two steps. What counts is the square where the Lion started his entire move/turn, and the position after finalizing the entire move/turn. The situation half-way is irrelevant.

In that light, I cannot agree with any of your points, and also do not see how they fill in my rule gap.

It's the same with casting. Castling is one King's move. It's not that after displacing the King , we look at the Rook and if that was seen by a Time Thief than the Rook part can be reverted and the Rook captured.