Choose which stick sandwich definition you are testing
The thinkorswim reference requires a bearish first candle in a downtrend, a bullish second candle opening above the first close, and a bearish third candle closing at the first close. TA-Lib uses a stricter middle-candle location: its low must exceed the first close. TA-Lib permits a configurable equality tolerance and does not test the preceding downtrend.
- A middle candle can open above the first close and still dip below it. That passes the stated opening comparison but fails the stricter low comparison.
- The specification below uses the stricter location, an explicit prior-decline filter and a tick-based equality rule. It is a custom research definition, not a claim to reproduce TradingView, thinkorswim or TA-Lib defaults.
- Candle color is determined by close versus open. A hollow or green chart display alone is insufficient if the chart uses a different color convention.
Define the OHLC and close-tolerance rules
Number the three completed ordinary candles 1, 2 and 3, oldest first. O, H, L and C mean open, high, low and close. Let q be the symbol minimum tick and N be a nonnegative integer tolerance in ticks. This example sets N = 2; the allowed price difference is T = N × q.
- TradingView exposes the chart dataset minimum tick as syminfo.mintick. It is a price increment, not a pip or the cash value of a futures tick. Read it for the actual exchange-qualified symbol.
- For tick-aligned OHLC, compare the integer tick coordinates of the two closes. This prevents decimal floating-point noise from rejecting an exact boundary. Verify alignment first; do not silently round malformed or differently adjusted data into a match.
- Reject missing history, a nonpositive tick, invalid OHLC ranges or open/close values outside their high-low range. This definition adds no body-length ratio, shadow-length limit or third-candle opening gap.
- A two-tick rule has no universal market significance. On a coarse-price grid it may be wide relative to the candle body. Record the tolerance and inspect that scale before testing; changing it changes the population of candidates.
| Test | Rule |
|---|
| Prior decline | The three closes immediately before candle 1 decrease strictly |
| Outer bodies | C1 < O1 and C3 < O3 |
| Middle body | C2 > O2; a doji is excluded |
| Middle location | L2 > C1; equality fails |
| Close match | abs(C3 - C1) <= N × q; equality at the boundary passes |
| Strict mode | N = 0 requires C3 = C1 |
Two ticks mean different price distances
These hypothetical examples isolate the close-match test. Assume valid tick-aligned prices and that every other pattern rule passes. Price units are arbitrary; these rows are not quotes for particular instruments.
- The tolerance is symmetric. With q = 0.25, closes from 99.50 through 100.50 qualify in quarter-point steps; 99.25 fails. With N = 0, only 100.00 qualifies.
- Using a fixed 0.02 allowance on all three grids changes the rule: it is two ticks on the first, less than one tick on the second, and 200 ticks on the third. Decimal places alone do not define comparable tolerance.
| Minimum tick q | First close C1 | T at N = 2 | At the included upper edge | One tick beyond |
|---|
| 0.01 | 100.00 | 0.02 | C3 = 100.02: pass | C3 = 100.03: fail |
| 0.25 | 100.00 | 0.50 | C3 = 100.50: pass | C3 = 100.75: fail |
| 0.0001 | 1.1000 | 0.0002 | C3 = 1.1002: pass | C3 = 1.1003: fail |
Walk through a candidate and rejected near matches
Assume q = 0.25, N = 2 and prior closes of 105, 104.50 and 104 in chronological order. The hypothetical candles below form a candidate at candle 3 close. The matching distance is abs(100.25 - 100) = 0.25, or one tick, within the two-tick limit of 0.50.
- The middle candle has a positive 2.00 body and L2 = 100.25 > C1 = 100. Changing only L2 to 100 makes the strict location test fail, even though its open remains above C1.
- Changing only C3 to 100.50 still passes; 100.75 fails. Changing only C2 to 100.50 creates a doji and fails the middle-body rule.
- Changing the preceding closes to 104, 104 and 103.50 fails the strict decline filter. The three-candle shape can still exist without qualifying as this reversal candidate.
- The first and third lows differ, and both are below their closes. The close match therefore says nothing about an exact match of the lower extremes.
| Candle | Open | High | Low | Close |
|---|
| 1: bearish | 103.00 | 103.25 | 99.75 | 100.00 |
| 2: bullish | 100.50 | 102.75 | 100.25 | 102.50 |
| 3: bearish | 103.00 | 103.50 | 99.50 | 100.25 |
Separate confirmation, expiry and failed support
For a declared follow-through test, freeze U = max(H1, H2, H3) and D = min(L1, L2, L3). Watch the next three completed bars. The first close above U confirms the upward hypothesis; the first close below D invalidates it. If neither occurs, expire the pending candidate after the third close. These thresholds and the three-bar window are example research choices.
- Keep the original candidate time separate from the confirmation time. Later information cannot justify placing a confirmed historical signal on candle 1 or candle 3.
- This is a close-based event test, not an intrabar stop system. A bar may trade below D and recover before closing; that excursion does not invalidate this particular rule. A different rule using lows will produce different results.
- A confirmation does not establish a profitable trade. Entry timing, position size, costs, stop execution and exit rules remain separate; a gap can prevent a fill at the intended price.
| Independent path after the example: U = 103.50, D = 99.50 | Outcome |
|---|
| A later high is 103.75, but its close is 103.25 | Pending: a wick above U is insufficient |
| A later close equals 103.50 or 99.50 | Pending: the boundary tests are strict |
| The next close is 103.75 | Confirmed at that close |
| The next close is 99.25 | Invalidated; the matched closes did not hold |
| The next three closes are 101.00, 102.00 and 103.50 | Expired without confirmation |
| A close of 103.75 confirms, then price later closes at 99.25 | Record later failure without deleting the earlier confirmation |
Stick sandwich versus tweezer bottom
TradingView describes a tweezer bottom as two candles with nearly identical lows, with bearish then bullish bodies after a decline. Stick sandwich uses three candles and matches the first and third closes. Substituting lows for closes changes which pattern is being measured.
| Feature | Stick sandwich | Tweezer bottom |
|---|
| Number of candles | Three | Two |
| Body sequence | Bearish, bullish, bearish | Bearish, bullish |
| Matched price | First and third close | First and second low |
| What the match establishes | A measured close-level relationship | A measured low-level relationship |
Review the detector before testing a strategy
Give Pine Script AI Coding Agent the OHLC rules, tick tolerance, prior-close filter and follow-through window to draft a detector. Request separate candidate, confirmed, invalidated and expired events, evaluated on completed bars. Review the generated source and request syntax checking before comparing its output with these cases.
- Record the symbol, timeframe, session, adjustment settings, timestamps and raw OHLC values for both matches and rejected near matches. Keep ordinary candles and the price feed consistent across the review.
- Use AI Chart Analysis to review a screenshot of the visible trend and candle sequence. Compare a hit with a failure sample. Retain the numeric OHLC alongside the image: pixels cannot certify a one-tick difference or recover off-screen history.
- Only after the detector matches the declared rules should you specify strategy orders and test outcomes. Compilation, image agreement and pattern counts do not establish a trading advantage.
