Puzzles
Set by the data desk. Solutions print the following day, upside down, as is proper.
Cryptogram No. 441
A simple substitution. The setter reminds you that the hardest ciphers in this newspaper's history have all been the ones where somebody used a real key.
Acrostic No. 113
Fourteen clues. The initials of the answers, read downward, give a phrase this newspaper prints more often than any other. Every answer is somewhere in the archive — the setter says that is not a hint, it is the puzzle.
- 1 What went into the basin by the door in May 1847 (8)
- 2 It explains 71 per cent of persistence; the day of the week explains 0.2 (8)
- 3 The town below the hill the order named itself after (9)
- 4 Why thirteen ships came home six weeks early (3)
- 5 Days the forestry office took to answer a boring question (4)
- 6 The constellation every other horoscope column leaves out (9)
- 7 What Europe's most secret order filled in, in 1956 (4)
- 8 What all nine of the Texas specimens turned out to be (7)
- 9 The word she carried at the foot of fourteen stories for three years (10)
- 10 Strongest lines in the spectrum of the burning ball (7)
- 11 The Arizona paper that printed the story and no photograph (9)
- 12 The ness with the light on it, 8.4km on a bearing of 106 (6)
- 13 What the impulses are recorded on (9)
- 14 What number 401 was, before it was a ship (4)
The setter's hint
The key is not clever. It has been used by every schoolchild who has ever written a note in a lesson, and it is the reason this newspaper's data desk laughs whenever a document arrives “encrypted”.
Eight Signatures. Everyone Was Where They Said. One Entry Still Cannot Have Happened.
The last two puzzles failed on geography and on a clock. This one has nobody in the wrong city and nobody moving faster than an aeroplane, and one entry is impossible anyway.
Custody Chain No. 1 hid a signatory in the wrong city. No. 2 hid a folder that could not have travelled in the time given. Both were caught by readers in under a quarter of an hour, which is a compliment to the readers and a note to the setter.
This one is different. Every person below was in the city they signed in. Nothing moves faster than an aeroplane. The chain runs in order. One entry is impossible anyway.
The registries
- Reykjavík registry — city centre, forty-five minutes from Keflavík.
- Oslo annex — inside the airport terminal. No transfer time.
- Tallinn store — city centre, twenty-five minutes from the airport.
- Riga office — city centre, twenty minutes from the airport.
None of those distances matters this week. They are printed because the series prints them now, and because a reader who has to ask whether they matter is doing the right thing.
The chain
| # | Date | Received by | At | Signed |
|---|---|---|---|---|
| 1 | 3 Feb | A. Okonjo-Halstead | Reykjavík registry | 10:15 |
| 2 | 11 Feb | B. Fairweather-Sunda | Reykjavík registry | 14:40 |
| 3 | 19 Feb | C. Delacroix-Whitby | Oslo annex | 09:05 |
| 4 | 24 Feb | D. Bergkamp-Rios | Oslo annex | 16:20 |
| 5 | 29 Feb | E. Amankwah-Pryce | Tallinn store | 11:00 |
| 6 | 6 Mar | F. Adeyemi-Strand | Tallinn store | 08:30 |
| 7 | 14 Mar | G. Oyelowo-Vasquez | Riga office | 13:45 |
| 8 | 21 Mar | H. Sarpong-Ashby | Riga office | 10:10 |
All dates are 2026.
Where the eight were
- Okonjo-Halstead — Reykjavík, the whole of February.
- Fairweather-Sunda — Reykjavík, 8 to 14 February.
- Delacroix-Whitby — Oslo, 17 to 22 February.
- Bergkamp-Rios — Oslo, 23 February to 2 March.
- Amankwah-Pryce — Tallinn, the whole of February and March.
- Adeyemi-Strand — Tallinn, 4 to 9 March.
- Oyelowo-Vasquez — Riga, 12 to 18 March.
- Sarpong-Ashby — Riga, from 20 March.
The answer
Entry 5. Amankwah-Pryce was in Tallinn for the whole of February, so she is in the right city. The Tallinn store is where the folder should be by then. The time is unremarkable. Her itinerary, the geography and the clock all pass.
2026 is not a leap year. There was no 29 February.
The entry is signed on a day that did not occur.
This is the failure that gets through, and it gets through for a reason worth naming. A solver checking a custody chain builds a mental table of people and places, because that is what the previous two puzzles trained them to do and what a forger is assumed to get wrong. The date column is treated as an index rather than a claim. It is read to order the rows, not to be tested.
Every real document examiner this newspaper has spoken to says some version of the same thing: the cheapest forgery to catch is the one with an impossible date, and it is also the one that survives longest, because the people checking are busy with the interesting part.
Custody Chain No. 4 has nine entries and no impossibility at all. The chain is sound. What is wrong with it is somewhere else, and it is not in the table.
Seven Signatures. Two Are Impossible. One Of Them Is Only The Clock.
A reader broke last week's puzzle in fourteen minutes and then found a flaw the setter had not intended. This one states where every registry stands, because that was the flaw.
Custody Chain No. 1 gave six entries and hid one impossible signature among them. Forty-one readers found it. Wilhelmina Sarpong-Ashby found a second problem the setter had not put there — an entry that survived only because the puzzle never said whether the registry was at the airport or in the town.
So this week every registry comes with its address. That is not decoration. One of the two impossibilities below cannot be seen without it.
Seven entries. Two of them cannot have happened. One fails on geography. The other fails only on the clock.
The registries
- Perth registry — city centre, twenty minutes from the airport.
- Singapore annex — inside the airport's cargo terminal. No transfer time.
- Zurich store — city centre, fifteen minutes from the airport.
- Lisbon office — city centre, thirty minutes from the airport.
Zurich to Lisbon is a two-hour-forty-five-minute flight. Nothing else in this puzzle turns on a flight time.
The chain
| # | Date | Received by | At | Signed |
|---|---|---|---|---|
| 1 | 4 Apr | A. Okonjo-Halstead | Perth registry | 09:10 |
| 2 | 4 Apr | B. Trelawny-Boye | Perth registry | 17:40 |
| 3 | 9 Apr | C. Delacroix-Whitby | Singapore annex | 11:05 |
| 4 | 12 Apr | D. Vandenbroucke-Ige | Singapore annex | 14:20 |
| 5 | 16 Apr | E. Adeyemi-Strand | Zurich store | 08:50 |
| 6 | 16 Apr | F. Sarpong-Ashby | Lisbon office | 11:30 |
| 7 | 21 Apr | G. Oyelowo-Vasquez | Lisbon office | 13:30 |
Where the seven were
- Okonjo-Halstead was in Perth for the whole of April. He is in this puzzle for the same reason he was in the last one, which is that he signs for everything and goes nowhere.
- Trelawny-Boye was in Perth from 2 to 6 April.
- Delacroix-Whitby was in Singapore from 7 to 14 April.
- Vandenbroucke-Ige was in Zurich until 12 April and in Singapore from 13 April.
- Adeyemi-Strand was in Zurich for the whole of April.
- Sarpong-Ashby was in Lisbon from 14 April.
- Oyelowo-Vasquez was in Lisbon from 18 April.
The rules
A folder cannot be received by someone who was not in that city that day. It cannot arrive somewhere before it has physically got there. And the chain runs in order.
The answers
Entry 4 fails on geography. Vandenbroucke-Ige was in Zurich until 12 April and did not reach Singapore until the 13th. She cannot have signed in the Singapore annex on the 12th. This is the same shape as last week's answer and most solvers will find it first.
Entry 6 fails on the clock, and only on the clock. Every person in it is in the right place: Sarpong-Ashby has been in Lisbon since 14 April, so the signature is unremarkable. The folder is the problem. It was in the Zurich store, in the city centre, at 08:50. Fifteen minutes to the airport, a two-hour-forty-five-minute flight, thirty minutes from the Lisbon airport into town: three hours thirty at the very best, and that assumes an aircraft waiting with its door open. The folder cannot be in Lisbon before 12:20. It is signed for at 11:30.
Nobody in entry 6 is lying about where they were. The entry is impossible anyway.
That is the whole reason the addresses are printed this week. Put the Zurich store at the airport and entry 6 becomes merely tight. Put the Singapore annex in the town and entry 3 becomes questionable too. A custody chain that does not say where its registries are is not checkable, and a great many real ones do not say.
Custody Chain No. 3 has eight entries and one impossibility, and the impossibility is in a date nobody thinks to check.
Six Signatures. One Of Them Is Impossible. Can You Find It?
A new puzzle for the back of the book. You are given six custody entries for a single folder and the movements of the six people who signed them. Exactly one entry cannot have happened. Find it.
A third puzzle joins the acrostic and the cryptogram, and it is the one this newspaper should probably have run first, because it is the thing the documents desk does all day.
A custody chain is a list of who held a folder, where, and when. A forged chain almost never fails on the signatures. It fails on the geography — somebody is recorded receiving a folder in a place they could not have been.
Below is a chain of six entries. Below that, what we know about where each signatory was. Exactly one entry is impossible. The other five are consistent.
You do not need any outside knowledge. Everything required is on this page.
The chain
| # | Date | Received by | At | Signed |
|---|---|---|---|---|
| 1 | 3 Mar | R. Okonjo-Halstead | Perth registry | 09:40 |
| 2 | 7 Mar | T. Bergkamp-Rios | Perth registry | 16:05 |
| 3 | 11 Mar | A. Delacroix-Whitby | Singapore annex | 11:20 |
| 4 | 14 Mar | W. Oyelaran-Tasker | Singapore annex | 08:15 |
| 5 | 19 Mar | C. Adeyemi-Strand | Zurich store | 14:50 |
| 6 | 22 Mar | H. Oyelowo-Vasquez | Zurich store | 10:30 |
What we know about the six
- Okonjo-Halstead was in Perth for the whole of March. He signs for a great many things and has never been anywhere interesting.
- Bergkamp-Rios flew Perth to Singapore on the evening of 7 March and did not return.
- Delacroix-Whitby was in Singapore from 9 March to 16 March, then Zurich from 18 March.
- Oyelaran-Tasker was in Zurich until the morning of 14 March, and in Singapore from the 15th.
- Adeyemi-Strand was in Zurich for the whole of March.
- Oyelowo-Vasquez was in Singapore until 20 March, then Zurich from the 21st.
The rule
A folder cannot be received by someone who was not in that city on that date. It also cannot be received in a city it has not yet travelled to — the chain runs in order, and a folder in Zurich on the 19th cannot be back in Singapore on the 22nd.
The answer
Entry 4. Oyelaran-Tasker was in Zurich on the morning of 14 March and did not reach Singapore until the 15th. She cannot have signed in the Singapore annex at 08:15 on the 14th.
Every other entry survives. Bergkamp-Rios signs in Perth at 16:05 on the 7th and flies that evening, which is tight but legal. Delacroix-Whitby is in Singapore on the 11th and Zurich from the 18th, so entry 3 holds and she is not needed again. Oyelowo-Vasquez reaches Zurich on the 21st and signs on the 22nd, with a day to spare.
The reason this puzzle is worth setting is that entry 4 is the only one that looks completely ordinary. It has a plausible name, a plausible time and the same city as the entry above it. The impossible entry in a real forged chain is almost never the strange one. It is the one that matches its neighbour.
Custody Chain No. 2 runs next week and has seven entries and two impossibilities. One of them is in the times.
Acrostic No. 112 — 'The Annex Trick'
Fourteen clues. The initials, read downward, give the piece of advice this newspaper's FOIA correspondent gives more often than any other.
Answer the fourteen clues. Read the first letter of each answer downward. The phrase is four words, and a reader who has been through our Reading Room column has already been told it.
- Not a redaction, merely a leak (5)
- What an examiner may raise but rarely issues (7)
- The Ur site, in its Arabic name: Tell al-_______ (8)
- Bergen's discipline, in this paper's Loch Ness story: fisheries ________ (11)
- What eight of the nine Texas specimens had (5)
- This paper's document prefix (2)
- Neither Teros nor surface-dweller (5)
- What a bid-stage drawing may dimension but not build (5)
- The interval System D will not define (14)
- What Mr Pell has been 3,388 times (5)
- Number of talents short of the schedule (5,7)
- The Vault's third drawer (8)
- What we could not confirm, in a word (7)
- Where the fault was not (with the ________) (7)
Last week's solution, No. 111
The phrase was NOTHING STAYS HIDDEN FOR LONG, which is the gloss of this newspaper's motto and which the setter concedes was guessable from the enumeration alone.
Eight hundred and ninety readers solved it. Forty-one wrote in to point out that the motto is aspirational rather than descriptive. The setter agrees and has been overruled by the editor, who says the puzzle page is not the place.
Last week's solutions
Cryptogram No. 440. A COMMITTEE THAT KEEPS NO MINUTES HAS NOT FORGOTTEN. IT HAS DECIDED.
Fourteen hundred and eleven readers solved it. The fastest correct solution arrived nine minutes after publication from a reader in Ipoh, Malaysia, who has now been first four weeks running and who the setter would like to state, for the record, is welcome to a job.
Acrostic No. 111. The phrase was NOTHING STAYS HIDDEN FOR LONG, which is the gloss of this newspaper's motto and which the setter concedes was guessable from the enumeration alone. Forty-one readers wrote in to point out that the motto is aspirational rather than descriptive. The setter agrees and has been overruled by the editor, who says the puzzle page is not the place.