Bishop vs. Rook?

"Why is a bishop worth less than a rook?" ... A reasonable question. If you put a bishop and a rook in the middle of the board they control the same amount of space. Bishops can be brought into the action quickly with the fianchetto but rooks have to wait till the endgame. Bishops are not commonly forked but rooks are, there are whole entire openings just devised to forking the queen and the rook. So I was wondering why are bishops worth three points but rooks worth five? PLEASE SAY WHY you think rooks are worth two points more then bishops. Thanks for taking the time to read. --FifthDimension

Rook+King against King can mate. Bishop+King against King can't

@ trysts Yes thats a very good reason

-Bishops can only ever reach half the squares on the board.

@ waller I don't see what you are talking about.

@davepacker another good point. I'm too lazy to actually count the squares up. I never said I'm standing up for bishops, but what about 2 bishops vs. 2 rooks?

2 rooks can checkmate on their own. 2 bishops can't.

one rook can form a barrier that the king can't cross, but it takes two bishops to do that.  two rooks can form two barriers and keep the king in a corner.  i am not good at two-bishop mates, but i don't think you can do it without a king.  whereas you certainly can do it with two rooks and not move your king around. 

as for the rooks being forked.  it is not like bishops can't be forked, or even aren't forked.  but the statement that rooks are more commonly forked, is more proof that rooks are more powerful.  if someone forks your bishop and your rook, you will usually move your rook.  just like if someone forks your rook and your queen, you will usually move your queen. 

hahahah, too funny.  bishops are so awesome you promote a pawn to a bishop for the powerhouse of the two bishop endgame. 

FifthDimension: you are asking right kind of question here which is always a good starting point for improvement. I believe there are two main reasons: 1) the bisop can never reach half of the squares on the chess board; 2) the rook controls as many squares on the empty board no matter where it's placed whereas a bishop in the corner controls only 7 as opposed to 13 of bishop in the centre.

Altough the rook is considerably stronger than a bishop in general (especially so on an open board) their relative strength also depends on the position - especialy on the pawn structure. Note that both the bishop's action and the rook's action can be severely restricted by own or enemy pieces blocking their diagonal/file. Thus if the position is such that there are open diagonals for bishops and no open files for the rooks it can happen that the bishop is almost as strong as a rook or even stronger - but this is an exceptional situation.

No, there aren't.

 Yes the Italian Game puts Imediate pressure on blacks king and the fried liver attack is another opening.

 Yes two bishops can mate although it's easier with too rooks.

You need another piece (even if its the king) to checkmate with 2 bishops. 2 rooks can checkmate by themselves.

No, those openings weren't devised for the purpose of forking the Q & R and winning material. That would require really poor play by Black.

 Oh ok you didn't make that very clear.

 Actually it doesn't

Yes it does. To say that totally standard openings are completely busted is ludicrous. 

 I don't want to argue with you but get a chess book and look up the fried liver attack, also I just dug back through my room and looked at all my games I've played in the last month and exactly 86% of the time I was whiteI beat my opponent with a Queen and Rook fork. Like the one below.