Concepts
The 14 principles the coach retrieves from, and the whole curriculum behind the app. Every citation in a game note links back here, every drill quotes the “when it applies” line from one of these pages, and nothing the coach says is grounded in anything else — so an explanation can always be checked against the principle it rests on.
Tactics
7Patterns that win material in a move or two. These are what the coach cites most, because they are what most games turn on.
- Overloaded defenderA piece asked to guard two things at once guards neither reliably. Find the second job, then take the first.One enemy piece is the only thing defending two of your targets. Count defenders on each target and see if the same piece appears twice.
- Double attackOne move, two threats. The opponent answers one and loses the other. Queens and knights make the cheapest ones.After any candidate move, list everything the moved piece now attacks. If two of those are worth taking and both are undefended, you have one.
- Loose pieceUndefended pieces are what tactics are made of. "Loose pieces drop off" — check every piece you own before moving.Point at each of your own pieces in turn and name what defends it. Anything with no answer is loose, and every tactic in the game runs through it.
- Back-rank weaknessA castled king behind three unmoved pawns has one escape square: none. Every rook on the first rank is a threat.Look at your own king. If f7, g7 and h7 are all still on their squares and no piece guards the eighth rank, you are one rook away from being mated.
- ForkA single piece attacking two targets at once. Knights fork best because their attacks cannot be blocked.For knights, look for two enemy pieces a knight's move apart from a common square — kings and rooks on the same colour are the classic pair.
- PinA piece that cannot move without exposing something more valuable behind it. Add attackers before it escapes.Look along your bishops', rooks' and queen's lines for two enemy pieces in a row, with the more valuable one behind.
- Discovered attackMove the front piece and the piece behind it does the work. Strongest when the front piece also makes a threat.Look for your own pieces standing on a line between one of your long-range pieces and something of theirs worth hitting. The front piece is the one to move.
Position
7Slower advantages. Nothing here wins a piece today; all of it decides who has the easier game in twenty moves.
- Central controlPawns and pieces that cover d4, d5, e4 and e5 restrict the opponent's pieces before any tactic exists.Count how many of your pieces and pawns hit d4, d5, e4 and e5, and how many of theirs do. The side with more usually has the freer game.
- Open diagonalA bishop's value is the length of its unobstructed diagonal, not the square it stands on.Follow each bishop's two diagonals with your eye until they hit something. A bishop that stops after one square is doing nothing.
- Bishop pairTwo bishops cover both colours. In open positions the pair is worth roughly half a pawn over bishop and knight.Check whether you still have both bishops and they do not. If so, look for ways to open the position rather than to trade.
- Open fileRooks need files with no pawns. Occupy the file, then contest it — the side that doubles first usually keeps it.Scan the eight files for one with no pawns of either colour on it, and for half-open files with only the enemy's pawn.
- Rook activityA rook that sees nothing is worth less than a knight that sees six squares. Activity outranks material in rook endings.Count the squares each rook can legally move to. A rook defending a pawn from behind it usually has one; the same rook attacking from the seventh has ten.
- King safetyA king stuck in the centre with open files nearby is a permanent tactical liability — even a pawn down, keep it stuck.Ask whether the king has castled, whether the files beside it are open, and whether the pawns in front of it have moved. Two of those three going wrong is usually enough for an attack.
- Trading logicTrade when it helps your worst piece or hurts their best. Trading a good knight for a passive bishop is a concession.Before any capture, compare the two pieces by what they are doing rather than by their point value. The question is which of you will miss it.