British Go Journal No. 15.  Autumn 1971. Page 5b.
J. T. Fairbairn
I'm sure most people have at some time or other felt they had won a game only to be robbed of victory at the last moment by a 'swindle'. Unfortunately too many of these people seek solace in commiseration, and fail to learn obvious lessons.
The first step is to concede that 'swindle' is generally a misnomer. To swindle someone is to deprive them of their property by pretence, fraud or cheating. We can all think of examples of this in Go, especially if we count as cheating: blowing smelly pipe smoke over your opponent as he is thinking; the coffee gambit; knocking the board over, etc. - all usualy old tricks from chess days. I was once confronted in a vital tournament with an extremely décollétée female opponent. I count that as cheating, though I'm ashamed to say I managed to win.
However, that is not what we normally refer to as a swindle. The loss of a huge territory or group resulting from an impertinent play inside your territory is also the result of a perfectly legitimate move, well within the rules and unashamedly blatant in its intention. This is not a swindle, aggrieved though you may feel at the time.
The distinction is important, because in a genuine swindle there is not much you can do about it within the rules themselves. You could then justifiably feel hard done by. But, in the case of the 'cheeky' player, the only recourse is to realise his play is fair, to pull your finger out (as they say) and not sit back and wait for the reward for your sorely-tried patience in heaven.
You must, and can, do something about it within the context of Go. The first stage is obviously to try to work out the possible combinations. If this is too difficult or worrying your next step is to count the game and see whether you can afford to sustain a loss. (In doing this you may even find that your only hope is to try a 'swindle' yourself.) Further counter-measures could be ko or seki. Should none of these possibilities offer hope you will have to try to kill the invader. Even here you can use your replies to the optimum. Having decided that you cannot afford to sustain the loss, or resort to ko or seki, you must then concentrate on cutting off the intruder first, then killing it. It now makes absolutely no difference whether your opponent goes further and further into your territory so long as he is cut off and has no eye shape. In fact most beginners seem to play defensive moves and aggressive moves alternately in such a situation. If they use those moves wasted in defending part of their territory, they would have twice as many attacking moves and thus twice the chance of killing the invader.
In fact, the whole problem is one of an attitude of mind. Firstly, in recognising the situation for what it is, secondly, in deciding on a course of action and sticking to it. This may seem obvious, but the inability to play consistently to a plan is often mentioned by professionals as marking the difference between professionals and amateurs. Haruyama once went so far as to say it was best to play consistently even though you found halfway through that your plan was bad!