In the financial market, a well-developed trading system is the cornerstone of success. Let's delve into the core elements of a trading system and the importance of the MACD indicator.

First, any effective trading system is built on four key pillars:
1. Accurately assess market trends
2. Accurately select the timing and position for entry
3. Scientifically set stop-loss and profit targets
4. Reasonable application of capital management strategies

It is important to note that two key principles should be followed when building a trading system:
- Even when using common indicators, it is necessary to conduct extensive backtesting to verify their profitability before gradually putting them into practice.
- Maintain the simplicity of the system; the simpler it is, the easier it is to execute, as long as it ensures profitability.

When it comes to specific indicators, the MACD is undoubtedly one of the traders' preferred tools. Its importance is reflected in:
1. MACD is a time-tested and efficient technical indicator, widely favored by professionals.
2. The MACD derived from moving averages has unique insights into trend grasping and is an essential tool for trend investors.
3. The MACD's divergence at tops and bottoms is recognized as one of the most reliable reversal signals, providing strong support for capturing market turning points.

By mastering MACD and combining it with a complete trading system, investors can better identify market highs and lows and seize swing trading opportunities. Remember, successful trading requires not only reliable tools but also continuous learning and practice. By constantly optimizing the system and improving judgment ability, every trader has the opportunity to find their own path to profitability in the market.