T101 system initially was designed for tandem trade identification.
The tandem pairs suggested by trader101 are perfectly 'correlated'. I try not to use the word 'correlate' but I can't find another English word. You can imagine they are chained in market movement.
Like the original correlation theory, correlation coefficient changes through time and economic fundamental change.
I never like this. Yes, tandem pairs work but for a certain period of time only.
However, T101 can be used to identify potential tandem trades. As suggested by trader101 too, we shall trade the very few pairs that cross-jump (crossover). These are the few leader pairs. These pairs can change according to market condition too. For instance, I observed leading pairs changed from GBPJPY to USDCHF as time changes.
It does not matter anyway.