Jane Street's Monthly Puzzles are public challenges in logic, mathematics and creative problem solving. A new puzzle appears every month or two, and the official archive contains previous puzzles and their solutions.
Open the current puzzle, work out the requested final answer and submit it through Jane Street's form. Only the initial submission qualifies, so verify the answer and its format before pressing submit.
What are the Jane Street Monthly Puzzles?
Jane Street offers standalone puzzles for people who enjoy tackling unusual problems. Some involve filling number grids or finding geometric patterns, while others demand probability calculations, careful counting or an unexpected interpretation of a clue.
The series reflects the emphasis Jane Street places on identifying and solving difficult problems. It is a public puzzle activity rather than a stage of the firm's job application process.
Release cadence
A new challenge every month or two.
How to participate
Read the current puzzle and submit your answer online.
What you can explore
Earlier puzzles, official solutions and listings of correct solvers.
Start at the Jane Street puzzles hub. Its current puzzle and archive links are the most useful starting points, regardless of when you discover the series.
How to find and start the current puzzle
The current challenge is always reached from Jane Street's current puzzle page. Read the full instructions, including any illustrations and examples, before deciding what you need to calculate or submit.
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Read the actual question
Separate the story, the mathematical rules and the final requested quantity. Write one sentence describing exactly what counts as a valid answer.
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Record every constraint
For a grid, note allowed values, adjacency, connected regions and clues. For a word puzzle, list recurring structures and anything deliberately unusual about the wording or presentation.
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Work through a small case
Test the rules on an easier grid, shorter sequence or smaller graph. This often reveals the intended invariant or a contradiction that rules out entire families of guesses.
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Verify the final answer
Check every constraint against the finished construction and recompute the exact quantity requested. Submit the answer in the form specified by that puzzle rather than a loosely related intermediate result.
For a first attempt, choose an archived puzzle and keep its solution hidden until you have a serious approach of your own. This gives you a way to practise without using hints from an active challenge.
How to submit an answer and appear on the leaderboard
Use the submission form directly beneath the current puzzle. It requests an email address and answer, and offers optional name or username, comments and an option to have your name added to the leaderboard.
| Form item | What to do |
|---|---|
| Enter a working email address for the submission. | |
| Answer | Use the precise number, word or other result requested in the puzzle instructions. |
| Name or username | Enter the name you want associated with your entry, if desired. |
| Leaderboard option | Select the option if you want your name considered for public recognition. |
| Questions or comments | Add a note only when it contributes something useful to your entry. |
Jane Street states that only initial submissions qualify. Treat the first answer as final: use an independent calculation, a second constraint check or a short script to catch mistakes before you send it.
After submission, return to the puzzle pages to see the eventual answer and recognition of correct solvers. Past official solution pages include lists of correct submissions, while the current form lets participants opt into leaderboard visibility.
Recognition is the practical outcome to aim for, rather than an assumed cash prize or a recruiting advantage. Any special reward or extra condition belongs to the instructions for the individual puzzle.
What kinds of puzzles does Jane Street publish?
The archive ranges from mathematical constructions to problems whose rules must be discovered from visual or verbal clues. These examples provide a useful tour of the skills that recur without implying that every puzzle follows one standard format.
| Puzzle family | Official example | What to practise |
|---|---|---|
| Grid constraints | Hooks 10 | Combine local clues, connected regions and restrictions on neighbouring cells. Identify forced placements before guessing. |
| Number placement | Number Cross 4 | Translate row clues and regional digit rules into arithmetic constraints. Reject partial grids as soon as one clue fails. |
| Probability and graphs | Andy's Afternoon Amble | Model random movement using states, transitions and return events. Derive a small case before solving the full walk. |
| Language and pattern discovery | Regional Artwork | Test word lengths, repeated letters, ordering, visual patterns and extraction rules instead of assuming the question is purely numerical. |
| Geometry and symmetry | It's a Metric, Too | Partition a grid into permitted regions, track distances and compute the requested aggregate only after checking the construction. |
Start with a puzzle family that matches your strengths, then switch to one that does not. The most useful improvement comes from learning how to translate unfamiliar wording into rules you can actually test.
A reliable method for solving harder Jane Street puzzles
Strong solutions usually come from choosing a representation that makes invalid possibilities easy to eliminate. For a grid, that might be a table of candidate digits; for a movement problem, it might be a graph of reachable states.
1. Turn the story into a model
Assign a variable to each unknown and translate every statement into a constraint. If a region must be connected, draw the possible connections; if a walk ends on a return, specify the state and stopping rule.
2. Separate necessary conditions from guesses
Look for parity, divisibility, totals, conservation laws and bounds. A necessary condition can eliminate a candidate immediately, even if it does not prove that the remaining candidate works.
3. Find a forced move and propagate it
Choose the row, region or state with the fewest legal possibilities. After each placement, update the others before exploring another branch.
4. Search systematically when deduction stalls
List the remaining cases in a fixed order and reject each as soon as it breaks a rule. If you use Python, encode the constraints first, then make the search produce a complete candidate that can be checked by hand.
5. Verify both the construction and the submitted value
A valid grid and the puzzle's requested answer are often two separate things. Recalculate row totals, areas, path lengths or probabilities from the final construction, then make sure the number you submit is the right one.
A good stopping point for each solving session is a written list of proven constraints, remaining cases and one next test. This makes it easier to return to a difficult puzzle without restarting the reasoning.
EverythingQuant practice puzzle with a worked solution
This original number grid exercise illustrates constraint propagation, one of the most useful techniques for Jane Street style logic puzzles. It is an EverythingQuant practice problem, not a question from the Jane Street archive.
The challenge
Place the digits 1 through 9 into the nine cells below, using each digit once. The three numbers in every row must increase from left to right, and the column sums must be 12, 15 and 18 respectively.
The top left cell is 4 and the centre cell is 8. What three digit number appears in the bottom row?
| Row | Column 1 | Column 2 | Column 3 |
|---|---|---|---|
| Top | 4 | ? | ? |
| Middle | ? | 8 | ? |
| Bottom | ? | ? | ? |
| Column sum | 12 | 15 | 18 |
Reveal the worked solution
The middle row must end in 9 because its final digit has to exceed 8. The middle column totals 15, so its top and bottom entries must sum to 7.
The top middle entry must exceed 4, which makes it at least 5. The bottom middle entry must be at least 2 because a smaller positive digit must appear to its left, so the only possible pair is 5 and 2.
Now the bottom left entry is 1. The left column gives 4 + 7 + 1 = 12, forcing the middle left entry to be 7.
The only unused digits are 3 and 6. Since the top row increases from 4 to 5, its final digit must be 6, leaving 3 for the bottom right cell.
| Row | Column 1 | Column 2 | Column 3 |
|---|---|---|---|
| Top | 4 | 5 | 6 |
| Middle | 7 | 8 | 9 |
| Bottom | 1 | 2 | 3 |
| Column sum | 12 | 15 | 18 |
The answer is 123. All nine digits appear once, every row increases and all three column sums match, so the grid satisfies the full set of constraints.
Try this technique on a larger archived grid by marking forced cells before testing alternatives. It is faster and more convincing than checking arbitrary completed grids.
When Python helps and when it gets in the way
Code is useful when a puzzle has many legal placements, repeated calculations or a probability model with numerous states. It works best as a verifier or a disciplined search tool rather than a substitute for understanding the constraints.
The following Python checks all arrangements for the original practice grid. It prints the number of valid solutions and the bottom row answer, providing an independent check of uniqueness.
from itertools import permutations
solutions = []
for cells in permutations(range(1, 10)):
a, b, c, d, e, f, g, h, i = cells
if a != 4 or e != 8:
continue
if not (a < b < c and d < e < f and g < h < i):
continue
if (a + d + g, b + e + h, c + f + i) != (12, 15, 18):
continue
solutions.append((100 * g + 10 * h + i, cells))
print(len(solutions), solutions[0][0])
# Output: 1 123The script checks 9 factorial possible assignments, which is 362,880 cases, and finds exactly one valid grid. For larger puzzles, prune partial assignments as soon as a sum, adjacency or connectivity condition fails rather than generating every complete candidate.
Always test a program against a small example you can solve manually. A script that returns one answer is not convincing unless the code captures every rule and the result passes a separate check.
How to practise with the puzzle archive
Use the official puzzle archive as a set of progressively different problem types. The objective is to improve your solving method, not to memorise archived final answers.
| Session | Exercise | Checkpoint |
|---|---|---|
| 1 | Try an older Hooks puzzle. Write down its region and adjacency constraints before filling cells. | Identify three placements or exclusions that are logically forced. |
| 2 | Work on Number Cross. Translate each clue into a condition you could check on a partial grid. | Explain why at least two candidate placements fail. |
| 3 | Use a simpler random walk to prepare for Andy's Afternoon Amble. | Derive the probability of a return in two steps before adding states. |
| 4 | Try Regional Artwork or another word puzzle. Catalogue unusual features without opening the solution. | Produce two testable hypotheses and reject one with evidence. |
| 5 | Return to your hardest unsolved puzzle, check your reasoning and open the official solution afterward. | Record one new technique and one mistake you want to avoid next time. |
This EverythingQuant practice sequence is designed to build repeatable solving habits. Spend enough time to reach a meaningful deduction in each session, and use the official explanation to learn the technique you missed.
Do Jane Street puzzles help with quant interviews?
Solving these puzzles develops habits useful in technical interviews: making assumptions explicit, testing a model, exploring edge cases and explaining why a solution works. The public monthly puzzle series is separate from Jane Street's recruitment assessments and interview rounds.
For trading interview preparation, combine puzzle solving with focused probability, expected value, estimation and decision making practice. Jane Street's puzzle archive tests creative persistence, but it is not a complete replacement for role specific interview study.
For the hiring process itself, see EverythingQuant's Jane Street Trader Interview Guide. To strengthen the probability fundamentals behind many quantitative problems, use the Probability for Quants course.
Jane Street Monthly Puzzles frequently asked questions
How often does Jane Street release a new puzzle?
Jane Street posts a new puzzle every month or two. Check the current puzzle link rather than assuming a fixed day of the month.
Can I participate without applying for a job?
Yes. The puzzle page is public and has its own answer submission form, separate from Jane Street's recruitment applications.
Can I submit a corrected answer later?
Only your initial submission qualifies under the current puzzle form's instructions. Check your answer carefully before submitting it.
Where can I find previous puzzle answers?
The official archive lists past puzzles alongside their solution pages. Attempt the puzzle before viewing its solution if you want to use it for practice.
How do I get my name on the leaderboard?
Submit the correct answer and opt into leaderboard recognition using the option on the current puzzle form. Official solution pages for past puzzles also show correct submissions.
Do these puzzles award prizes or jobs?
The regular activity is solving a public puzzle and potentially receiving recognition. Do not assume a prize, interview or job offer from a submission; use the specific puzzle's instructions for any additional reward terms.
Can I use code to solve Jane Street puzzles?
Programming can help with enumeration, graph searches and checking arithmetic when the puzzle permits it. Understand the model and test its assumptions rather than trusting an unexplained output.
Official Jane Street puzzle resources
Use Jane Street's own pages to start a new puzzle and review previous answers. The examples below are archived problems, so their solutions can be studied without spoiling an active challenge.
- Jane Street Puzzles: series overview and links to the current challenge and archive.
- Current Puzzle: active problem and official answer form.
- Puzzles Archive: earlier prompts and official solutions.
- Hooks 10: connected regions and number placement.
- Andy's Afternoon Amble: probability and movement on graphs.