When the market enters a downtrend, there is actually more than one common way to judge it; instead, multiple signals can be referenced.

Trendlines and moving averages serve as confirmations in terms of patterns—when the price consistently runs below them, it indicates that bears are in control.

Support and resistance focus more on structure—when rebounds are repeatedly blocked at the previous low area, it shows a lack of buying strength.

The death cross is a classic indicator signal—when the short-term moving average crosses below the long-term moving average, it means the downtrend is likely to continue.

These methods do not exist independently but rather corroborate each other. Truly high-probability scenarios are never based on a single signal; only when trendlines, moving averages, structure, and indicators all point to the same conclusion can the downtrend be considered confirmed.

In other words, determining the trend can't be done at a glance; a closed loop must be formed, using multiple methods for cross-validation.