The second lesson on Technical Indicators Practice "Bollinger Bands Channel" has concluded. In two hours, we thoroughly reviewed Bollinger Bands from basic concepts to practical applications. If your previous impression of Bollinger Bands was just "three lines, sell at the upper band, buy at the lower band," then today's class should have completely refreshed your understanding.

1. What did we learn today?
1. What are Bollinger Bands?

They consist of three lines: the middle band (MA20, indicating direction), the upper band (middle band + 2 standard deviations, resistance level), the lower band (middle band - 2 standard deviations, support level). Core idea: prices mostly fluctuate within a normal range; exceeding the range often indicates extreme market conditions, but extremes do not necessarily mean an immediate reversal.

2. Strong and weak zones — the first indicator of direction

Strong zone: price between the middle and upper bands → only go long, no shorting

Weak zone: price between the middle and lower bands → only go short, no going long

Neutral oscillation zone: price moving around the middle band → sell high and buy low or wait and see

Mnemonic: Above the middle band only go long, below the middle band only go short, near the middle band wait for direction.

3. Four core functions

Support and resistance: in ranging markets, upper and lower bands are effective; in trending markets, the middle band is a better reference.

Overbought and oversold: price deviation does not necessarily mean reversal; must filter with candlestick patterns, divergence, RSI, etc. In trending markets, deviations can persist.

Trend identification: the slope of the middle band determines trend direction; bandwidth changes indicate trend strength.

Channel contraction and expansion, and trend reversal prediction: narrowing → brewing direction; widening → trend initiation. Volume breakout after contraction is one of the most reliable trading signals.

4. Horn-shaped pattern — classic strategy

Open mouth: after bottom consolidation, volume breakout above the upper band, horn opens → buy signal

Closing mouth: high-level stagnation, upper band turns down, price breaks below the middle band → sell signal

Tight mouth: long-term decline with the three bands narrowing, very low volatility → bottom area, wait for breakout confirmation

5. Practical combination strategies

+KDJ: buy on the lower band + KDJ low-level golden cross; short on the upper band + KDJ high-level death cross.

+RSI: lower band + RSI bottom divergence is a very strong reversal signal; upper band + RSI top divergence, decisively exit.

+Volume: breakout must be accompanied by volume; retracement should see decreasing volume. Breakouts with no volume are unreliable.

6. Special adjustments for cryptocurrencies

Major coins (BTC/ETH) can use standard parameters (20,2); altcoins need to increase the standard deviation to 2.5 or even 3.

For 24-hour trading, hourly levels can use (12,2) or (10,2).

During flash crashes or surges, Bollinger Bands may distort; overlay ATR or switch to longer periods.

7. Six common mistakes

Counter-trend operations in trending markets (most fatal)

Blindly using default parameters

Cycle mismatch

Treating brief penetrations as true breakouts

Overloading indicators and conflicting signals

Lack of risk control

2. The core philosophy of this lesson
The middle band sets the direction, the upper and lower bands define the boundaries. Oscillate by selling high and buying low, follow the trend during pullbacks. Use horn patterns to catch breakouts, and narrowing channels to anticipate reversals.

The greatest value of Bollinger Bands is not "top-timing and bottom-fishing," but helping you distinguish between ranging and trending markets, then adopting different strategies. Use the upper and lower bands for high-probability sell and buy in range-bound markets, and rely on the middle band for pullbacks in trending markets. Many losses come from treating trending markets as ranging markets — always trading against the trend and losing money.

3. Post-class homework
Open the Bitcoin daily chart, set Bollinger Bands (20,2), identify two opening patterns, two closing patterns, and two tight patterns of horn shapes over the past year, and save screenshots.

On the 4-hour chart, find a segment where the price moves between the middle and upper bands in an uptrend, and another where it moves between the middle and lower bands in a downtrend. Observe the slope of the middle band.

Use Bollinger Bands + KDJ or + RSI on a demo account to find three resonance signals and record the results.

4. Next lesson preview
MACD — the king of momentum indicators, how to use divergence at tops and bottoms to catch trend reversals.

MACD can tell you whether the trend's momentum is strong or weak, when it accelerates, and when it exhausts. Combining with Bollinger Bands and moving averages, your technical analysis system will form a complete closed loop.

Please familiarize yourself with basic concepts like MACD golden cross, death cross, zero line, green and red bars, divergence, etc.

Bollinger Bands are not difficult; what’s hard is overcoming the human tendency to want to trade against deviations. Remember: your feelings are not important; signals from the channel are what matter. I am Wang Yibo, see you in the next class!

Wishing your account stays in the green!