The ADX indicator can be used to employ trend-following or counter-trend strategies for trading GBP/JPY, depending on the market conditions and your risk appetite. For instance, you can enter a long position when the +DI line crosses above the -DI line and the ADX line is above 25 and rising, suggesting a strong and increasing bullish trend. Similarly, a short position can be taken when the -DI line crosses above the +DI line and the ADX line is above 25 and rising, indicating a strong and increasing bearish trend. Additionally, you should exit a long position when the +DI line crosses below the -DI line or the ADX line falls below 25 or turns downward, showing a weakening or reversing bullish trend. Likewise, you should exit a short position when the -DI line crosses below the +DI line or the ADX line falls below 25 or turns downward, indicating a weakening or reversing bearish trend. Finally, it's best to avoid trading when the ADX line is below 20 or flat, implying a choppy or sideways market.