The following are replies I made to 1245's comments:
[....one use is simply to enter both sides at an important price level and then exit one position based on the following price movement.
It's mainly used to avoid missing a strong move away from or through such price levels after which there is no reaction on which to enter.
This came up last night in a discussion about trading tactics when a non-native English speaker asked me what you call it in English. I only trade on reactions, but as I remember he places a stop loss order for each position which often eliminates missing an entry due to the time that would be needed to place a new order in the direction of the breakout. I can see often getting whipsawed doing this, but he claims it's very favorable on balance.]
As I said above, I enter trades on reactions only. And when I said that during the discussion we were having the point was raised about TSE's new computer system with which big breakouts often happen in the blink of an eye, and without a following reaction. One person in the group explained his way of entering on breakouts. I'll try to explain it as I remember.
Let's say the Nikkei Mini runs up to 17000 and goes into a consolidation between 17000 and 16900. On the following breakout we often see a move of 50 yen so. As stated, the move is often too fast to catch. So what he does is, if price movement permits, is to go long and short at say 16995, and places a stop loss at say 17030. If the price breaks out to 17050, he is long and plus 20, and doesn't miss the entry, which is the purpose of this tactic. If it's a false breakout the halts at 17020, he's still flat. His risk is a false breakout that hits his stop. But his experience shows him that the advantage of being in on those moves more than covers the few small losses taken on false breakouts.
Anyway, this tactic is not my cup of tea, so I didn't listen that attentively to his explanation and might be missing a part or two. But after his explanation he asked me what this type of position is called in English. I know what it's called in Japanese, but not in my native language of English. Dictionaries list 'cross trade', but that's different. So that's why I asked on ET, but my simple question opened up a can of worms!!