#Gate广场四月发帖挑战 This article teaches you how to use the three lines of Bollinger Bands (upper band, middle band, lower band) to judge market trends and find buy and sell opportunities. It also explains how to avoid pitfalls and manage risks. The content can be divided into these sections:

First, understand the “basic usage” of Bollinger Bands: It was invented by John Bollinger in 1983. The core is three lines — the middle band is the 20-day moving average, the upper band is the middle band plus 2 times the standard deviation, and the lower band is the middle band minus 2 times the standard deviation.
The channel formed by these three lines indicates the magnitude of price fluctuations: the wider the channel, the more intense the price swings; the narrower the channel, the more likely a quick trend reversal (78% of the time, narrow channels precede big moves). The middle band acts as a “trend boundary line”: if the price deviates too far from the middle band, it’s likely to revert back.
How to interpret “buy and sell signals”:
Trend signals: When the price breaks through the middle band with increased volume (more than the 20-day average volume), and three consecutive candles stay above the middle band, it’s a reliable bullish signal; breaking below the middle band indicates a bearish trend.
Reversal signals: When the upper and lower bands are very close (contracted by more than 20%), like “squeezed” together, it suggests an upcoming breakout — either a volume-driven move above the upper band or below the lower band. But don’t rush to buy on the first breakout; 30% of these may be false signals. Wait for the close confirmation for more reliability.
Overbought and oversold signals: When the price moves above the upper band, it indicates “overbought” conditions, and you might consider selling some; when it drops below the lower band, it indicates “oversold,” and you might consider buying a little more. Also, if the price stays outside the bands for more than 4 candles, there’s a 68% chance it will revert toward the middle band, suitable for short-term profit-taking.
How to use different trading timeframes:
Short-term (intraday trading): Watch 15-minute and 1-hour charts, use the 4-hour chart for the overall trend, set a 2% stop-loss and 3% take-profit, and avoid greed.
Mid-term (swing trading): Use 4-hour and daily charts, refer to the weekly middle band to decide whether to buy or sell. If the upper and lower bands are expanding at more than 45°, it indicates a strong trend, allowing you to hold longer.
Long-term: Use weekly and monthly charts. When all three lines are trending upward, consider a firm buy-and-hold strategy for at least 3 months. If the channel width on the monthly chart exceeds the maximum of the past three years, it could signal a market top or bottom, suitable for phased position building.
Don’t rely solely on Bollinger Bands; combine with other indicators: Relying on Bollinger Bands alone can lead to pitfalls. Use RSI, MACD, and volume for confirmation. For example, if the price hits a new high but RSI doesn’t, it’s a “bearish divergence” and likely to fall. If MACD shows a bullish crossover (buy signal) while the price breaks above the middle band, the upward move is more reliable.
Additionally, volume during breakouts should be at least twice the 30-day average; otherwise, it might be a false breakout.
Risk management is paramount:
Stop-loss and take-profit: After buying, if the price falls below the middle band, sell quickly — don’t hold through the loss. After selling, if the price breaks above the middle band, cut losses and exit. You can also sell in stages, e.g., sell 30% when the price hits the opposite band, then sell another 40% on a pullback to the middle band.
Leverage usage: When the price breaks the bands, reduce leverage; when the channel is narrow, you can slightly increase it. The higher the leverage, the stricter the stop-loss should be. For example, with 5x leverage, accept a maximum loss of 1%; with 20x leverage, only 0.25%. Never risk more than 5% of your total capital on a single trade.
Avoid false breakouts: For short-term signals (like 15-minute charts), always check the longer-term trend (like 4-hour charts). If the price hits a new high but the channel doesn’t widen or volume doesn’t increase, it might be a false breakout — don’t follow blindly.
How to handle special situations:
Extreme market conditions (e.g., rapid price surges or crashes): Increase the channel multiplier from 2x to 3x to prevent frequent false signals. If the channel suddenly widens more than 3x within 24 hours, be alert for black swan events and reduce leverage immediately.
Range-bound or choppy markets: Adjust the middle band period to 10 days for more sensitivity. If the price fluctuates less than 20% of the channel width and volume is low, consider staying out of the market and avoid unnecessary trades.
Black swan warnings: If major coins and Bitcoin’s channels expand abnormally at the same time with high correlation, it could indicate systemic risk. Prepare hedging strategies in advance.