brownsfan, back to blackjack, my favorite casino game.
From your description, it didn't seem you were playing basic strategy?
Here is what I find interesting about Blackjack. If you play perfect basic strategy, the casino's edge is only 0.3%. Which means that after having played 100 hands you will have lost 3x you're bet. Yet most players I see lose their whole stake in less than 50 hands while I usually double mine in that same time (I have never left a casino having lost money at blackjack).
How can that be when we are all sitting at the same table? First of all, most player don't even know basic strategy so they don't make the right decisions on some hands. Big mistake is that they don't double when they should. But this is not the main reason they lose. They lose because of poor money management. For example, the minimum bet is £5 and they arrive with £30 at the table. You are guaranteed to lose with that amount of money because of the huge variance (winning and losing streaks) that you can expect when playing.
Yet I win? And I don't count cards (I am usually drinking instead and talking to my fellow players). Why do I win? Luck - pure luck, but I take advantage of luck. How? I just play basic strategy to minimize the casino's edge and quit when I have doubled my money. I double my money not because of any skill, just because of the variance. While playing, I might lose half my stake due to variance but I know I will break even if I keep playing since this is a 50/50 game in the long run. Then I will make money due to variance (luck) again. I then just quit. It makes perfect sense. You can do this in any 50/50 game. Just don't bet more than 5% or 10% on each hand to avoid risk of ruin.
And I recommend not varying your bet size. I always regret it.
Now to trading: What are you opinions applying this to trading? Assuming you have no edge (or just enough to cover commissions), shouldn't you be able to make money using this strategy?