DAY 9: Oscillator – Basics of RSI and Stochastic

In the last time (DAY 8), we learned trend analysis using moving averages.

This time, we will explain the代表s of oscillator indicators used to grasp the market’s “momentum” and “overbought/oversold,” oscillator-type indicators, RSI and Stochastics, as a representative.

Both are widely used from beginners to professional traders, but simply saying “buy/sell because the number is ○○” often leads to traps. Let’s learn the basic idea and practical usage.

1. What are Oscillator Indicators?

• Oscillator indicators quantify price and volume data into numbers and display within a fixed range (e.g., 0–100).
  
  
• Primarily used to determine overbought/oversold and to gauge market “momentum” or to identify potential reversal timing.
  
  
• Often used in conjunction with trend indicators such as moving averages; effective for finding pullbacks or retracements in trending markets and reversal points in ranging markets.
  
  

2. RSI (Relative Strength Index)

(1) The basic mechanism of RSI

• Formula(details omitted)
  • Compares the upward and downward movements over a certain period to quantify how strong buying pressure/selling pressure is in the market.
• Value range
  • Ranging from 0 to 100. Generally, above 70 indicates overbought, below 30 indicates oversold.
    
    

(2) Typical usage

1. Reversal signals
   • When RSI exceeds 70, there is a high possibility of short-term overextension upward.
   • When RSI falls below 30, there is a high possibility of short-term overextension downward.
   • Thus, “consider selling when above 70” or “consider buying when below 30” is commonly discussed.
2. Divergence usage
   • When price makes a new high but RSI does not, or price makes a lower low while RSI does not, this is called “divergence,” and is considered a sign that momentum is waning.It’s also said to indicate a potential trend exhaustion.
   • RSI as well as oscillators like Stochastics can be used for divergence analysis.
     
     

(3) Notes

• In a trending market, prices can continue rising even if it’s overbought
  • If you enter a sell position merely because RSI is above 70, you may get hurt in strong uptrends.
• Period settings affect usability
  • Typically 14 periods is the default, but 5, 9, 21, etc. can be tried to suit you better.
    
    

3. Stochastics

(1) The basic mechanism of Stochastics

• Calculation concept
  • Within a period’s high-low range, quantify where the current price sits.
  • There are lines called “%K” and “%D,” and their movements are used to judge overbought/oversold.
• Value range
  • Generally displayed from 0–100; above 80 indicates overbought, below 20 indicates oversold.
    
    

(2) Typical usage

1. Cross lines to judge buy/sell
   • Stochastics often displays two lines (%K and %D).
   • For example, when %K crosses below %D from above 80, that is a typical sell signal.
2. Divergence checks
   • Similar to RSI, divergence with price movements can be analyzed.
     
     

(3) Notes

• Good with range markets, but many false signals in strong trending markets
  • In uptrends, price can stay above 80 for a long time, and signals may fail to appear even as price rises.
• Signals can be too fast
  • Because of high sensitivity, there can be many false signals.
  • With experience, slower stochastics or adjusting the period can reduce noise.
    
    

4. Example combinations: Trend × Oscillator

(1) Moving Average + RSI

• Direction of the trend is inferred from the moving average (MA: if it’s rising, consider a buy bias).
• Then, if RSI falls near the 30 area indicating “oversold,” consider it a pullback entry for buying, etc.
• This is a trend-following reverse-positioning, so the success rate tends to be relatively higher.
  
  

(2) Bollinger Bands + Stochastics

• Treat ±2σ of Bollinger Bands as resistance and combine with 80/20 on Stochastics to anticipate a possible rebound.
• However, during strong trends, price may frequently pierce ±2σ, so set clear stop-loss levels.
  
  

(3) Trend × Oscillator × Price Action

• For example, “MA is rising → RSI rebounds from around 50 → candlesticks break out” as a layered justification.
• This combination aims to complement each indicator’s strengths/weaknesses and reduce whipsaws.
  
  

5. Pros & Cons of Oscillators

Pros

1. Provides objective measures for overbought/oversold.
2. Can anticipate signs of weakening momentum (divergence, etc.).
3. Very effective in ranging markets.
   
   

Cons

1. Less effective in strong trending markets(reverse signals may cause squeezes or losses).
2. Setting periods and sensitivities is difficultShort settings yield too many signals; long settings may respond too slowly.
3. Divergence does not always guarantee a reversal (timing can be hard).

6. Summary & Next Time Preview

Summary

1. RSI and Stochastics are oscillator indicators that check whether the market is oversold/overbought within a 0–100 range.
   
   
2. Oversold = 30 or 20 and overbought = 70 or 80as a guideline.
   
   
3. Divergence(discrepancy between price and indicator) can be a hint for a trend reversal.
   
   
4. Combine with trend indicatorsto target pullbacks and retracements in trending markets and contrarian plays in ranging markets.
   
   
5. Auto trading (EA) also uses them, but the signal quality varies with adjustments, so thorough testing is essential.
   
   
   

Next time (DAY 10) Theme: MACD – Check Trend and Momentum at the Same Time

• Following RSI and Stochastics, we will study MACD, a hybrid indicator with trend and oscillator elements.
  
  
• It’s a popular indicator that can be used multi-dimensionally for trend direction, momentum, and divergence-based reversal signals.
  
  
• By broadly understanding these indicators, you’ll have a powerful tool for discretionary trading and automated trading. Please look forward to it!
  
  
  

If you are interested in automated trading, please also check the link below.
https://www.gogojungle.co.jp/users/147322/products

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Thank you.