ES, 5-minute chart, morning session. Five green candles in a row, each bar delta positive: +80, +65, +45, +30, +20. Buyers are pressing; the hand reaches for the Buy button.
Now look at price. Five candles, but the market moved only two ticks. Two ticks in 25 minutes while every bar shows positive delta. Where did all that buying go?
Bar delta alone will not answer. Each candle looks bullish in isolation. But if you put the deltas side by side, the energy fades: every next bar contributes less than the previous one. To see this fading without opening every footprint, you need to accumulate delta into one curve.
From bar delta to CVD: why accumulate
Bar delta is the territory of the previous module: Ask minus Bid for one candle. One bar, one snapshot. CVD is the film made from those snapshots.
Construction is simple: a running sum. First bar delta +80 gives CVD = +80. Add the second bar +65, CVD = +145. Add +45, CVD = +190, and so on.
| Bar | Bar delta | CVD (running total) | Price close |
|---|---|---|---|
| 1 | +80 | +80 | 5525.25 |
| 2 | +65 | +145 | 5525.50 |
| 3 | +45 | +190 | 5525.50 |
| 4 | +30 | +220 | 5525.75 |
| 5 | +20 | +240 | 5525.75 |
For five bars, CVD accumulated +240 contracts of net buying pressure, while price moved from 5525.25 to 5525.75: two ticks. Bar-by-bar view says, "green again, buyers are pressing." CVD view says something else: the slope is flattening, each new push is weaker, energy is draining.
CVD is the running sum of delta, bar by bar. Each bar adds its delta (Ask - Bid) to the accumulated result. Bar delta is a photograph; CVD is a film made from those photographs.
CVD has a cost. It is one line, one number per bar. It compresses the entire inner life of a candle into a single point. +50 from initiative buying at the high and +50 from a stop cascade at the low are the same contribution for CVD. The line knows HOW MUCH aggression there was, but not WHERE inside the candle it happened.
CVD limitation: one number per bar. CVD knows how much aggression occurred, but not where inside the bar. +50 at the high and +50 at the low are identical inputs.
Imagine a boat on a river. Rowers are aggressive buyers: each market order at ask is a stroke, and CVD accumulates those strokes. The current is passive sellers: limits, icebergs, algorithms. They do not initiate trades and are invisible to CVD. The boat is price.
Rowers row, CVD rises, but the boat is pushed backward and price falls. The current is stronger. And the unpleasant part: every stroke costs energy. The current is free. Sooner or later, rowers get tired.
When CVD and price diverge, it looks like this: price moves up while the CVD line below moves sideways or down. Two charts that should move together separate. That separation is the signal. The next step is to classify what kind of signal it is.
- CVD is the running sum of bar deltas (Ask - Bid)
- Bar delta is a photograph; CVD is the film that shows energy fading or accelerating
- CVD compresses a candle into one number and does not know where inside the bar aggression happened
- When CVD and price separate, you have a divergence that must be checked with footprint