In go, each move gets you points, by enlarging your territory (or saving your stones) or by reducing your opponent's territory (or capturing his stones). You've probably noticed that at the very end of a game, all the moves that players make are 1 pt. moves - pushing one point into his territory, capturing a single stone without making any change in territory, that kind of thing. On the other hand, you've probably also seen that some moves are worth huge numbers of points - especially moves that capture (or save) huge groups. That kind of move can be worth 60 pts., or more.

We also estimate the value of moves (as a sort of metaphor) even when there isn't a fixed amount of territory or stones changing hands. For example, the first move on an empty board is worth about 15 pts. After that, in general each move is worth less and less as the game goes on, until we get to the 1 pt. moves (everything cools down, so we say "the temperature [=points per move] is falling")... although as you've seen, when fights break out and stones come into contact, each move can be worth more and more (things are heating up, so "the temperature [=points per move] is rising").

If each move is worth a certain number of points, then it's fairly clear that if you keep passing while your opponent plays moves, you'll fall behind. (I pass, he plays a 10 pt. move... I pass, he plays a 10 pt. move... I pass, he plays a 9 pt. move: suddenly he's 29 pts. ahead of me.)

What's less clear, especially to beginners, is that playing a move that gains 1 pt. is closer to passing than to playing a move that gains 10 pts. (I play 1 pt, he plays 10 pts... I play 1 pt., he plays 10 pts... I play 1 pt., he plays 9 pts: he's 26 pts. ahead of me.) In fact, even if I capture a bunch of stones -- 5 stones, say -- I might still have lost points, if there are bigger moves on the board.

So when Ed says that "small moves" are a problem, what he means is that you're playing moves that gain 1 pt., or less, when you should be playing moves that gain 10 pts. Given that games are often lost by less than 7 points, a single small move can cost you the game.

Another way of looking at the question of what moves are small is to think about the stages of the game. In the very beginning, players are trying to stake a loose claim to different regions of the board, while maintaining good relations between their stones. Once both sides have staked out claims, those loose claims evolve into groups of stones, and each player tries to gain territory for himself while threatening the safety of the enemy groups. Once all the groups are alive, each player tries to squeeze out a few more points by making plays that settle the boundaries of the groups.

You won't be surprised to learn that staking out an empty area of the board is worth a lot of points; encroaching on an enemy group is worth quite a bit, but (often) less than staking out an empty corner; and settling the boundaries between the groups is (usually) worth very little.

So another way to understand Ed's advice is: you (usually) shouldn't play middle game moves in the opening, and you (usually) shouldn't play endgame moves in the middle game.

You might be wondering why Ed accuses you of making 0.5 point moves. How can a move be worth less than a point?

Let's say that there are two moves on the board that capture 10 enemy stones. The first one, your opponent has to reply to (otherwise you could kill an entire group). The second, he doesn't. Clearly you'll want to make the first capture first: that way you can capture the first 10 stones, he replies, and then you immediately capture the second group, for a total of twenty stones (forty points!). If you do it the other way around, you capture ten stones, and then he can save the other ten stones.

From this it should be clear that reducing your opponent's territory by 1 pt. is worth more when he responds than when he doesn't respond. And by the same token, assuming he doesn't respond, the 1 pt. reduction is worth more if you would have had to respond if he had played there (this is the same as saying that it would have been worth more for him to play there.)

For now, it's probably not worth worrying about why the move that one player needs to respond to (called sente, or reverse sente) is worth exactly twice as much as the move which neither player needs to respond to. But it's worth knowing it, because it's easy to get confused. You will frequently play moves that are clearly very good, without quite realizing that the move is sente (or reverse sente). Then later you'll play moves that are quite bad, but which look similar to the previous move, without realizing that this time, the move isn't sente (nor is it reverse sente). I believe this is a major reason why beginners play lots of small moves.

In go, a group of stones is trying to do a bunch of things at the same time. It's trying to get liberties... after all, if it runs out of liberties it's dead, and if gets close to running out, the opponent can boss it around. It's trying to get eyes... eventually, every group gets surrounded, and if it doesn't have eyes, eventually it will die. It's trying to shut in enemy groups.... that gives you more control over the rest of the board. It's trying to stay connected to other friendly stones... that gives them more liberties, more eyes, and keeps the enemy shut in.

And, of course, it's trying to do the opposite to enemy stones (take liberties, steal eyes, break through, cut apart).

Doing all of these at once is hard. You'll frequently find that the move that gets your group more liberties also makes it harder to connect to another group, or the move that connects makes it hard to shut in the enemy, and so on.

There are some shapes that accomplish several of these goals at the same time. You'll see them a lot in the games of stronger players, and over time you'll play them more and more in your own games. Go players tend to call these "basic shapes" or sometimes just "shape".

Now, you could try to learn about shape by reading and looking at examples on Sensei's Library. But you'll probably learn more, and have more fun, if you jump right in and play a lot of games, but play carefully, and at every move ask yourself: What are my goals for all my stones? Which of these goals are most important in this situation? Which move will combine these goals most effectively?