The essence of a ratache is to transfer to an adjacent line using a station's inherent spin as the initial impetus, and the current level of helical stress as a 'motor'. The result is a spinning move that can cover a worthwhile distance along the diagonal before coming to rest. Players blessed with exceptional timing were able to make lateral moves as well, but these moves were much rarer because the exact direction of a ratache is very hard to control with sufficient precision.
If helical stress is unfavourable, the distance a ratache can cover is greatly reduced. In these cases, a demi-ratache is a more prudent move. In optimum circumstances, a double ratache may be possible, but these are rare. In pathological cases, higher-level rataches would theoretically be possible, but these are likely to be dangerously imprecise.
The main attraction of the manœuvre, despite its comparatively short range, is that it requires few if any tokens to perform, and in using helical stress as a 'motor' it will slightly reduce the Brian field across the entire manifold. Naturally, that makes further rataches harder to perform.