Search for order blocks and you will find a thousand videos, most of them drawing rectangles on candles after the fact and calling it a strategy. The concept underneath is sound. The teaching around it is frequently terrible.
This guide sticks to what can be defended: what these zones represent, why price reacts at them, and how to mark them consistently enough that your results mean something.
The idea behind the zone
Every sharp directional move starts somewhere. Before price ran, it spent a short period going nowhere while someone built a position. When that position was large enough, price left the area quickly and did not come back for a while.
That origin area is the order block. The reasoning for why price returns to it is straightforward. An institution that wanted to buy 10,000 contracts at that level probably did not get all of them filled before price ran away. The unfilled portion of that interest sits there. When price returns, it meets that residual demand.
Supply and demand zones describe the same phenomenon with different vocabulary. Order block terminology came from one teaching lineage, supply and demand from another. The practical difference is mostly in how each camp defines the boundaries of the rectangle.
What makes a zone valid
This is where most traders go wrong. Any candle can be labelled an order block after price has bounced off it. The test has to be applied before the bounce.
Three conditions do most of the work:
1. The departure was violent
The move away from the zone should be fast and one-directional. Look for large-bodied candles, minimal overlap between them, and ideally a gap or imbalance. A slow drift away from a level means there was no urgency, which means there was probably no significant unfilled interest.
2. The zone broke structure
The move out of the zone should have taken out a prior swing high or low. A zone that produced a move which failed to break anything did not represent enough force to matter. This single filter removes most of the low-quality zones people mark.
3. The zone is untouched
The first return to a zone is the one that matters. Each subsequent test consumes more of the resting interest. By the third touch there is usually nothing left, which is why zones that have already been tested twice are poor trade locations.
How to mark a zone
Consistency matters more than which convention you pick. Choose one and apply it to every chart.
A common approach for a bullish zone: find the last down-close candle before the impulsive move up. Draw the rectangle from the low of that candle to its open. Some traders use the whole candle including wicks, others only the body. Bodies give tighter stops and more misses. Wicks give fewer misses and wider stops.
For a bearish zone, mirror it: the last up-close candle before the impulsive move down, drawn from its high to its open.
The important part is the last opposing candle. You are trying to isolate where the position was built, which is the pause before the move, not the move itself.
Imbalance and why it matters
When price moves so fast that a candle's range does not overlap with the range two candles earlier, it leaves an imbalance. Also called a fair value gap, this is a price region where trading was essentially one-sided.
Imbalances matter for two reasons. They confirm the violence of the departure, which is your first validity condition. And price has a documented tendency to return and trade through these areas later, which gives you an intermediate target between the current price and the zone itself.
A zone with a clean imbalance immediately above or below it is worth more than one without.
Trading the zone
Marking zones is analysis. Trading them requires rules.
Entry
Two approaches, with a real trade-off between them.
Limit order at the zone edge. You get the best possible price and the tightest stop. You also get filled on every zone that fails, including the ones price slices straight through.
Wait for confirmation. Drop to a lower timeframe, wait for price to enter the zone and print a structure shift in your favour, then enter. Worse price, tighter conviction, fewer catastrophic fills. Most consistently profitable traders using this approach take the second route.
Stop placement
Below the zone for longs, above it for shorts, with a buffer. Placing the stop exactly at the zone boundary invites a wick-out. How much buffer depends on the asset's volatility, and an ATR-based buffer is more defensible than a fixed percentage.
Targets
The nearest opposing zone is the obvious first target. Intermediate imbalances are reasonable places to take partial profit. Trading a zone without a target in mind turns a defined-risk setup into a guess.
Higher timeframe zones are worth more
A zone on the 4-hour chart represents far more resting interest than one on the 5-minute chart. It also has a wider boundary, which means a wider stop.
The standard resolution is to identify zones on a higher timeframe and refine entries on a lower one. Find the daily or 4-hour zone, then drop to 15 minutes to time the entry once price arrives. This gives you the significance of the larger zone with something closer to the risk of the smaller one.
Honest limitations
Several things about this approach deserve scepticism, and pretending otherwise does nobody any favours.
The institutional explanation is a story. It is a plausible story that matches observable behaviour, but retail traders cannot see institutional order books, and nobody marking rectangles on a chart knows what is actually resting there. The zones work often enough to trade; the reason they work may not be exactly the reason usually given.
The approach is also highly subjective. Two traders marking the same chart will produce different zones. That subjectivity makes backtesting hard and makes published win rates close to meaningless.
Finally, zones fail. In a strong trend, price runs through opposing zones without pausing. A zone is a location where a reaction is more likely, not a wall.
Building a routine
Mark zones on one market, on the daily and 4-hour charts, once per day. Write down the ones you consider valid and why, before price reaches them. Then record what happened.
After fifty marked zones you will have something most traders using this method never obtain: your own data on how often your zone definition produces a reaction. That number, not a video, is what tells you whether your version of the concept has an edge.