If you were to assign the king with a relative value...

...What would it be? :)

Along the lines of the points based table, where we acknowledge:

Pawn = 1

Knight = 3

Bishop = 3

Rook = 5

Queen = 9

Of course, I know this depends on the position you have. Sometimes having a queen against two rooks is favourable, or two minors against one rook.

Obviously, during the opening and middlegame you're seeking to protect the king, because losing the king is losing the game. But I often find that some of the opponents I play, (granted, I'm not that great myself... (yet!)) desperately try to avoid the endgame because they don't know how to utilise their king properly, especially if the middlegame shows that they're one for trying to gain exchanges as their main priority. I sometimes have problems with the endgame if the middlegame has been long and exhausting for me, because the middlegame is my weakest area and therefore a long middlegame can crush my confidence (and my time control!), but if I trade down to pawns with say a rook versus bishop quite quickly, I can often hold my nerve if my opponent is uncertain about what they have to do and I can use my king aggressively.

On that basis, I'd like opinions on how they would value the king as a piece in the endgame. :) Obviously, without the king, you can't deliver a basic mate, yet going by points, we all know that a mate with a solitary rook (5), is much easier to deliver than a mate with two bishops or knight and bishop (3+3). Yet on the road to delivering that mate, you need to utilise the king to eliminate your opponent's remaining forces (if it gets that far).

I would give the king a value of 3. On the basis that, like a knight, it can only deliver a maximum of 8 potential moves depending on its position. Knights have to move to alternating coloured squares between moves, and bishops are confined to the coloured squares they are upon throughout the game. Yet a king has greater flexibility and moves like a demi-queen. :)

What do other people think? Value it more? Value it less? In an end game with only pawns, the better positioned (centralised?) king will almost always secure the win. Whereas if there are other pieces left on the board, you'll do your best to mop up and block as many pawns as you can so your opponent can't promote.

As another minor diversion, what about the principle of whether or not the bishop should be valued sightly greater than the knight? :)

king = infinite

Comming up with a value for a king is utterly useless: the whole point of the 'point system' is to show the relative value of pieces. Thus we know that A rook is worth more than a knight, and so if there is a possibility of a trade we know that, in principle, it is a bad/good idea to do so. [b]Knowing the relative value of a piece is only meaningful when we can do something with it (i.e trade/sacrifice/promote)[/b]

But since the King cannot be traded or sacrificed, (nor can we be "up a king") it cannot have a 'value'... simply put, I say something meaningful when I say "A bishop is worth about 3 pawns" but to say "a king is worth about 3 pawns" is meaningless. Hmmm...maybe this only makes sense in my head.

Anyway, contradictions are fun: 3.5

if the king were a normal piece that could be traded off then I'd give it a 2.5

The King's true value is infinite. Some people assign an "attack value" to the King of between 2.5 and 3.5. The reason that the King is often left off the point count list, or given the value of infinity to set it apart from the rest, is because: if the King were actually worth, say, 3 points, that theoretically means that it would be acceptable in certain situations to trade it away for a Bishop or a Knight. Since losing the King equates to losing the game, as you acknowledge, this idea of trading the King is absurd, and so most people find no purpose in assigning the King any kind of value.

As to your other question: the Bishop is almost always listed as slightly more valuable than the Knight, simply by virtue of appearing before the Knight in hierarchical lists, even by sources that list them both as having the same value. Others say Bishop = 3.1, Knight = 3; or Bishop = 3.5, Knight = 3, etc. While this bothered me for a long time, I think it is probably justified. The two pieces are so different that they are very difficult to compare exhaustively. Many positions favor Bishops, many others favor Knights.

The reason that the Bishop is ever-so-slightly superior to the Knight, in my opinion, is this: Bishops are better in open positions, and Knights are better in closed positions. While this would set them equal, as long as a middlegame can be survived, it would eventually reach an endgame. Endgames, having fewer pieces on the board, are by their very nature less clogged than "closed" middlegames, affording Bishops at least a little more mobility.

Finally, an endgame will often, in theory, eventually reach a "late endgame" where (for example) it's B vs. N and both sides have pawns on one side of the board. This type of endgame tends to favor the Knight, since it can travel on either-color square while the Bishop is confined to one color. Still, while this diminishes the winning chances of the side with the Bishop, the Bishop can often be used very effectively to preserve a draw. Of course there are many exceptions to this.

But because the king can't be traded or sacrificed, if you've not had proper training / mentoring in chess, you might not appreciate how powerful the king can be (in the endgame).

Incidentally, whilst a pawn is valued at 1 in terms of material points, it is worth a hell of a lot more if it is passed, protected, and how far advanced up the board it is.

Therefore, if you are faced with a knight fork for example (with a check?) on a rook and passed pawn on the 7th rank with your king nowhere in sight of the pawn, you will almost certainly want to take the passed pawn to prevent a queen. :)

In an endgame of king and minor pieces, the king is the strongest piece. With rooks and queens on the board, he is a cowering old man that must be protected.

Numbers are fictitious.

People who go on and on about how the king doesn't have a value don't understand what the relative values are in the first place.  Pieces are assigned value in terms of mobility and the number of squares they can influence.  Of course in some cases it depends on how effective that influence is -- e.g. the well known example of a knight being more effective than a bishop when the action is confined to one area / one side of the board.

Or to put it another way, in general you'd rather have a minor piece blockade a pawn in an endgame than the king (king>3) and in general you'd rather have a king blockade a passer than a rook (king<5).  And indeed in may endgame lessons you'll see a minor pieces come to relieve the king of blockading duty or a king come over to relieve a rook.  So this is one practical application, to know which blockader is a more economic use of force.

Another application is in evaluating endgames.  In an endgame with pawns on both sides, you're looking at a line that ends up with your king on one side vs your opponent's knight... in principal the king vs knight on that side gives you an advantage on that side in force -- and depending on the pawns / weak squares you'll have good chances to promote if left alone.  And this is in any situation you're trying to decide which side to play the king onto in an endgame.  (In general) can your king+pawn hold off a knight and two pawns?  Sure.  Can a king hold off two pawns+knight, no way. etc etc.

I'd say the king isn't as much as 4, but certainly more than 3 -- 3.5 to 3.75 if you really had to know a number.  There are no exact values in chess anyway, (they're called the relative values for a reason) and it will always depend on the position.  That said, for the above reasons it's still useful to try and quantify in general terms the king's force.

the king's value starts at 1 for me. the longer the game progresses, the lesser the pieces left on the board, the higher the value of the king becomes. the king is a great compliment to any other pieces especially when you're trying to end the game. so it depends on which stage of the game you are before you judge what the rating of the king really is. that's my opinion.

3.5

eleventy-four

The king in that sense is worth about 3 points. See also the amazing recent video lecture by GM Dejan Bojkov, which I can warmly recommend!

http://www.chess.com/video/player/nominal-and-absolute-power-of-the-pieces-2

I've heard quite a few people note that an active king is worth about 4pts.  I can't say it made a ton of sense to me aside from points similar to orangehonda.

I treat it like a bit less than a knight as an attacker/defender early on, and a bit less than a rook in a cleared out ending.

The value of the king in terms of game continuation is infinite.  It must be protected at all costs since to lose it is to lose the game.  If you are trying to assess its fighting power it would vary depending on the types of opposition pieces still on the board.  I would say around 2.5 to 3 on the average.