Yes...the third touch is the one that validates the trendline.
Based on the Daily chart on the pair, we would only want to take short positions as this pair is trending strongly to the downside.
Based on the historical 1 hour chart of the GBPCHF
you posted, there are three things that can be used to analyze the trade: 1) if the pair trades up to the black trendline, a short position can be taken as long as the candle does not close above the trendline; 2) put a Fib line (red line) as shown and from the Fib levels a trader can determine the potential level of retracement…once that level is hit and the pair stalls at that level, a short position can be taken; and, 3) if the pair closes below support (green line) a short position can be taken at that point.
The idea here is that there is more than one way to analyze a chart depending on what is going on with the pair.