Part III, Institutional Chapter 13

The Open, Open Type, and Day Structure

By 09:45 you should know what kind of day this is going to be. By 10:30 you should be wrong only one time in five.

13.0Why this chapter exists

The cash open of RTH is the single highest-information event of the trading day. In the first 15 to 60 minutes, the resolution of overnight conditioning into a daytime regime is decided, and the day's playbook locks in. A trader who can classify the open type by 09:45 ET on ES has selected their framework four hours earlier than one who waits for end-of-day confirmation.

This chapter formalizes the open-type classification (Dalton's framework, six types reduced to a working five for this book), the IB extension probabilities, the 10:00 / 10:30 ET reassessment protocol, and the integration with prior-day structure (out-of-balance opens relative to prior VAH/VAL).

The chapter is one of the most operational. By the end, the reader has a daily 09:30 to 11:30 ET protocol that is mechanical and that selects the day's framework.

13.1The five open types (working taxonomy)

We use a five-type taxonomy that consolidates Dalton's framework for screen-trader operational use:

Open Drive

A forceful directional move from the open price, with little or no probe of the opposite side. The first 5 to 10 minutes establish a clear direction; price extends consistently through the IB period.

Signature in the first 15 minutes: - Direction in first 5 min: > 0.3% net move (up drive) or < −0.3% (down drive). - Wide range expansion 5 to 15 min relative to recent IB ATR. - Volume on the directional bars exceeds opposite-direction bars by 2x or more.

Implication: High probability of Trend Day. Continuation framework (Framework 2) is the playbook. Anti-pattern: do not fade IB extremes.

Open Test Drive

The session opens with a probe in one direction, fails (does not extend), then reverses sharply in the opposite direction.

Signature: - First 5 min: probe one way to a clear extreme. - 5 to 15 min: reversal that exceeds the probe extreme on the opposite side.

Implication: Trend day in the direction of the reversal. The probe-and-reverse confirms institutional rejection of the probe direction. This is often higher conviction than Open Drive because the reversal is the second signal (the rejection), and institutional intent is more visible.

Open Auction

The session opens around the prior close, slow, no decisive direction in the first 30 minutes. Multiple small probes in both directions, no clear extension.

Signature: - First 5 min: small range, near prior close. - 5 to 30 min: oscillation around the open without clear directional bias.

Implication: Range day with high mean-reversion probability. Range Fade framework (Framework 3) at IB extremes when they form. Anti-pattern: do not chase IB-extension breakouts without explicit confirmation.

Open Auction in Range

A subtype of Open Auction with even narrower oscillation. Multiple small probes both sides; price stays within a tight band.

Signature: - First 30 min: very narrow IB (< 0.5 × recent IB ATR median). - Volume below average.

Implication: Range day with smaller realized range. Same framework as Open Auction with tighter targets and stops.

Open Rejection-Reverse

The session opens with what looks like an Open Drive in one direction, but within 10 to 30 minutes the move reverses sharply through the opening price and continues in the opposite direction.

Signature: - First 10 to 15 min: appears to be Open Drive in direction A. - 15 to 30 min: sharp reversal that breaks through the open price and extends in direction B.

Implication: Often a Trend Day in direction B, but with a violent character. The morning's opening drive captured stops on direction A; the reversal reflects institutional players initiating in direction B at favorable prices. Reduce size by 25 to 50% relative to a clean Open Drive, because the entry timing is harder and the volatility is elevated.

Figure D13.1.Five open types and their characteristic price trajectories in the first 15 to 30 minutes. Classification by 09:45 ET locks in the daily playbook.

13.2Classification by 09:45 ET

The classification protocol on ES (adapt session times for other contracts):

Step 1, 09:35 ET (5 min after open)

Read the first 5-min bar's: - Direction (positive, negative, or near-flat?). - Range (compared to typical first-bar range over recent 14 sessions). - Volume (compared to recent average).

If direction is clearly positive or negative and range is wide and volume is elevated: candidate is Open Drive or beginning of Open Test Drive.

If direction is near-flat and range is small: candidate is Open Auction.

If direction is positive or negative but range is small: candidate is Open Auction in Range.

Step 2, 09:45 ET (15 min after open)

Read the next 10 minutes: - Has the directional move continued in the same direction? → confirm Open Drive. - Has the directional move reversed and exceeded the open in the opposite direction? → confirm Open Test Drive. - Has the range stayed compressed? → confirm Open Auction or Open Auction in Range. - Has the original drive direction reversed and broken through the open? → flag potential Open Rejection-Reverse.

By 09:45 ET, you should have a 70% confidence classification. The other 30% (ambiguous cases) become certain by 10:15.

Step 3, 10:00 ET (30 min after open)

For ambiguous cases (Open Rejection-Reverse candidates, late-developing Open Drives), the picture clears. By 10:00 ET, classification confidence should exceed 90%.

Step 4, 10:30 ET (IB completion)

The IB is now locked. Cross-check the open type against the IB structure: - Open Drive should produce a single-side IB extension or a strong directional IB. - Open Test Drive should produce a wide IB with both extremes touched. - Open Auction should produce a narrow IB. - Open Auction in Range should produce a very narrow IB. - Open Rejection-Reverse should produce a wide IB with the high and low both reaching extremes.

Disagreement between open type and IB structure is a flag: re-evaluate. Sometimes the open type was misread; sometimes the IB resolution was unusual.

13.3IB extension probabilities

After the IB completes at 10:30 ET, the next decision is whether the IB will extend (price moves beyond IB high or IB low) and in which direction.

Empirical extension probabilities by open type

These are practitioner consensus, calibrated on liquid ES sessions in 2024 to 2025:

Open Type	No extension	Single-side extension	Double-side extension	Strong directional
Open Drive	5%	55% (in drive direction)	15%	25% (Trend Day)
Open Test Drive	5%	60% (in reversal direction)	15%	20%
Open Auction	35%	35%	25%	5%
Open Auction in Range	50%	30%	18%	2%
Open Rejection-Reverse	8%	50% (in reversal direction)	12%	30%

These are illustrative; calibrate on your own contract and time period.

Single-side extension probability and direction

The open type also tells you which direction is most likely if there is a single-side extension:

Open Drive up: single-side extension is up with probability ~85% conditional on extension occurring.
Open Test Drive (reversed up): single-side extension is up with probability ~80%.
Open Auction: single-side extension direction is roughly 50/50; depends on which side is approached first.
Open Rejection-Reverse: single-side extension is in the reversal direction (the second move's direction) with probability ~75%.

Trade structure on IB extension

When IB extends:

Trend regimes (composite from Chapter 2): the extension is continuation; trade per Framework 2. Targets are 0.5x, 1.0x, 1.5x of IB range above (or below) IB high (or low).
Range regimes: the extension may be a false breakout; wait for the rejection at the extension high/low and trade per Framework 3.

Open type provides the prior; regime classification refines.

13.4The 10:00 ET reassessment

After 30 minutes of post-open trading, several things can have happened that warrant a re-check:

Re-check items at 10:00 ET

Open type confidence: is the open type still the same one you classified at 09:45? If not, why? Articulate the new classification.
Cross-asset: has VIX moved meaningfully? Has DXY moved? Has US10Y? Cross-asset shifts post-open often signal regime regimes that would not be obvious from price alone.
News: is there scheduled news in the next 30 to 60 minutes? If so, plan around it.
Volume: is volume on track relative to the 14-day average for this 30-min window? Below-average volume reduces the reliability of all subsequent setups.

Actions based on re-check

If everything is consistent: proceed with the framework selected at 09:45. If something has changed: pause; re-evaluate before sizing the next trade.

13.5The 10:30 ET reassessment (IB completion)

Now the IB is locked. The reassessment checklist:

Open type, final: confirm or revise.
Regime composite: has the composite from Chapter 2 stabilized into a clear classification? If yes, lock in the framework. If still transitional, hold off on tactical entries until 11:00 ET.
IB width: is the IB wide, normal, or narrow relative to the trailing 14-day median? Width informs the day's expected range.
First IB extension: has price already extended through one side? If yes, that side is the established direction; the next decision is whether the extension will sustain or fail.

Lock-in decision

By 10:30 ET, the day's playbook should be locked. Changes after this point are reactive (responding to new information) rather than primary.

The discipline matters because tactical drift (oscillating between frameworks during the session) is a leading cause of inconsistent execution. Lock at 10:30 ET; revisit only if the regime composite changes meaningfully.

13.6Open type combined with prior-day structure

The open is most informative when read against prior-day context.

Out-of-balance opens

From Chapter 10 (VWAP), the prior session's final VWAP is the institutional consensus benchmark. Today's open relative to that benchmark, combined with the prior-day VAH/VAL:

Open above prior VAH: "out-of-balance up." Today is pricing higher than yesterday's institutional consensus.
Open below prior VAL: "out-of-balance down." Symmetric.
Open inside prior VA (VAL ≤ open ≤ VAH): "in-balance." Today is starting in agreement with yesterday's structure.

Open type x balance interaction

Combining open type with balance produces a richer playbook:

Out-of-balance up + Open Drive up: highest-conviction Trend Day up. Multiple participants agree the market is repricing higher; the open drive confirms.
Out-of-balance up + Open Auction: today opened higher than yesterday's consensus, but the post-open is hesitant. Likely fade back to prior VAH or further into prior VA.
Out-of-balance down + Open Test Drive (reversal up): the down probe failed; institutional players are buying at the discount. High-conviction long.
In-balance + Open Auction: continuation of prior session's structure. Range fades dominate.

The matrix has 25 cells (5 open types × 5 balance states); not all are equally common, but each has a characteristic playbook.

13.7Day-structure narrative

The session's full structure unfolds across multiple phases:

Phase 1, Open (09:30 to 10:30 ET)

Open type classification.
IB formation.
First 30-minute volume and direction.
Regime composite begins to settle.

Phase 2, Mid-morning (10:30 to 12:00 ET)

Lock-in framework.
First IB extension or first range fade.
Watch for cross-asset shifts.

Phase 3, Lunch (12:00 to 13:30 ET)

Volume typically decreases.
Range often narrows.
Trend setups can fail in the chop; range setups can have wider stops.
Traders often reduce size during this window or stand down.

Phase 4, Afternoon (13:30 to 15:00 ET)

Volume re-expands.
Trend continuations resume; previously-faded levels may break.
News from European close (15:00 ET) sometimes flagged.

Phase 5, Pre-close (15:00 to 16:00 ET)

MOC (market-on-close) imbalance flow begins.
Order flow becomes mechanical (forced rebalancing).
Most discretionary frameworks lose validity.
Scale out of runners; flatten by 15:30 ET unless conviction is high.

Why phases matter

Each phase has different dynamics. A trade plan that ignores phase context (e.g., entering a fresh range fade at 14:30 ET when half the session is gone) is mistimed. The phases are part of the framework selection.

13.8Failure modes specific to open-type reading

Misclassifying the open at 09:45. The 09:45 read is provisional. Always re-check at 10:00 and 10:30. Most traders' open-type errors are caught by 10:30.
Treating Open Drive as automatic Trend Day. Open Drive raises probability of Trend Day from baseline ~20% to ~25% (per the table above). It is not a guarantee. Need composite confirmation.
Open Rejection-Reverse over-trust. This open type produces the highest-volatility sessions; sizing should be reduced, not increased, despite the visual conviction.
Ignoring news in the open window. A FOMC at 14:00 ET on a session with an Open Drive at 09:30 still requires news blackout; the open type does not exempt the protocol.
Short timeframe for classification. Trying to classify the open at 09:32 (2 minutes after open) is too early; one volatile bar is not an open type. Wait at least 5 to 10 minutes.
Confusing IB with first-30-min range. The IB is specifically 09:30 to 10:30 ET (60 minutes). The "first 30-min range" is a different measurement. Use IB consistently.

13.9The integrated stack treatment

Open type classification is Layer 7 of the institutional stack: structural levels (1) → volume profile (2) → AVWAP (3) → liquidity flags (4) → order-flow confirmation (5) → regime composite (6) → open-type classifier (7).

Open type is the daily playbook selector. It locks in framework selection by 10:30 ET. The lower layers (regime, OF, liquidity) execute the framework's setups within the day.

A daily plan structure:

09:00 to 09:30 ET: pre-market routine (Framework 0).
09:30 to 09:45 ET: open type provisional classification.
09:45 to 10:00 ET: confirmation; cross-asset re-check.
10:00 to 10:30 ET: IB formation; regime composite stabilizes.
10:30 ET: lock-in framework (Framework 2 if Trend, Framework 3 if Range).
10:30 to 14:30 ET: execute framework, with phase-aware adjustments.
14:30 to 16:00 ET: scale out, journal, prepare for next session.

13.10Diagram concepts referenced in this chapter

D13.1: Five open types side-by-side. Five small charts, one per open type, with the characteristic price trajectory in the first 30 minutes.
D13.2: 09:45 ET classification flowchart. Decision tree from "first 15-min direction" through range and volume gates to a final open type label.
D13.3: IB extension probability bar chart. Stacked bars per open type showing the four extension outcomes (no extension, single, double, strong directional).
D13.4: Out-of-balance open matrix. A 5x3 grid (open type × balance state) with the implied playbook in each cell.
D13.5: Day-structure phase diagram. A horizontal timeline of the session's five phases, with characteristic volume, volatility, and framework applicability marked.

13.12Exercises

Exercise 13.1: Open-type classification audit. For 30 ES sessions, classify each open type at 09:45 ET. Re-classify at 10:30 ET. Note discrepancies. Compute your own accuracy at the 09:45 timing.

Exercise 13.2: IB extension probabilities by open type. From the same 30 sessions, tabulate IB extension outcomes (none, single, double, strong) by open type. Compare to the table in §13.3. Calibrate the percentages to your contract.

Exercise 13.3: Out-of-balance open audit. For each session, classify open as in-balance, out-of-balance up, or out-of-balance down (relative to prior VA). Cross-tabulate with open type. Find the most common cells and the rarest.

Exercise 13.4: Phase-aware journaling. For each trade taken in your live trading week, tag the session phase (open, mid-morning, lunch, afternoon, pre-close). Compute win rate by phase. Most discretionary traders find win rates highest in mid-morning and afternoon, lowest in lunch.

Exercise 13.5: Open-type framework selection audit. For each of 30 sessions: (a) at 09:45 ET, what framework did you select? (b) what framework did the day actually call for in retrospect? Tabulate matches and mismatches. Use to calibrate your real-time classification skill.

Next chapter: cross-market context, VIX, DXY, US10Y, correlated futures, and how to use them to refine the regime classification and position sizing.