Definition. The Relative Strength Index of Bitcoin's daily closing price over a 14-day lookback, plotted against price. RSI compares the average size of recent up-moves with the average size of recent down-moves and maps the ratio onto a bounded 0-100 scale. Guide lines mark the conventional 70 and 30 thresholds, and days closing beyond either threshold are shaded behind the price.

Technical. Gains and losses are the positive and negative parts of the day-over-day change in the closing price. The first reading seeds both averages with a simple 14-day mean; every later bar applies Wilder smoothing, so the indicator is an exponentially decaying average rather than a fixed rolling window and retains a long memory of earlier bars. The series therefore begins 14 days after the first available price, and reaches 100 only when the smoothed average loss falls to zero. The shaded columns are drawn to the height of the daily close on days where RSI closes above 70 or below 30.

Interpretation. RSI measures the balance of recent momentum, not valuation. Sustained readings above 70 accompany trend continuation as often as exhaustion: across Bitcoin's full daily history the index has closed above 70 on roughly 14.5% of days but below 30 on roughly 3.5%, an asymmetry that follows from the long-run uptrend. Sub-30 readings are the rarer and more distinctive event and cluster in capitulation phases, while extended overbought stretches are a routine feature of impulsive advances. Divergence, where price sets a new extreme and RSI does not, carries more information than a threshold breach on its own.

Notes. The 70 and 30 levels are Wilder's original settings and are not calibrated to Bitcoin's return distribution; the shading marks threshold breaches rather than signals. Stochastic Oscillator measures the same 14-day window through position within the price range instead, and MACD through the spread between two exponential moving averages.