udgamlabs/logic-puzzles

UDGAM LABS · Dataset · 92,507 puzzles

Udgam Logic Puzzles

92,507 logic and reasoning puzzles in 17 families (knights and knaves, height orderings, zebra houses, cryptarithms, water jugs, knight moves, task schedules, calendars and more), each with one short answer that can be checked by exact match. Every question and every answer was produced by a Python program; no language model was used to write, solve or filter the puzzles. The generator is included, so you can make as many more as you need. Built for reinforcement learning with checkable rewards and for testing small models.

Puzzles	90,807 train, 1,700 test (100 per family); no question appears twice
Families	17
Answer	a number, a name, a weekday or a comma-separated list of names
Checks	a second, independent program re-solved all 92,507 from the question text alone: 100% agreement
Licence	data CC-BY-4.0; code (generator and checker) Apache-2.0

Quick start

from datasets import load_dataset

ds = load_dataset("udgamlabs/logic-puzzles")
row = ds["test"][0]
print(row["family"], row["question"], row["answer"], sep="\n")

Grading a model's reply (copy is_correct from logic_puzzles.py in this repo; it needs only the standard library):

from logic_puzzles import is_correct   # download logic_puzzles.py from this repo first

is_correct("lars,ana.", "Lars, Ana")             # True: case, spacing, quotes and a final full stop are ignored
is_correct("17.50", "17.5")                      # True: numbers compare by value
is_correct("Ana, Lars", "Lars, Ana")             # False: order matters where the question asks for an order

Extract the final answer from the reply first (for example, ask for it on a last line Answer: ...). Each question says what form the answer takes ("Answer with the number only", "in alphabetical order, comma-separated", and so on).

The 17 families

Family	What it asks	How the answer is computed	Train	Test
knights_knaves	Who are the knights, given what each islander says?	every truth assignment tried; exactly one fits	6,000	100
height_order	Order 4 to 6 people by height from pairwise clues	every order tried; exactly one fits	6,000	100
grid_paths	Count right/down paths through a grid with blocked cells	dynamic programming	6,000	100
variable_chain	Value of a variable defined through a shuffled chain of definitions with distractors	direct evaluation	6,000	100
calendar	Weekday of a date, or the number of days between two dates	calendar arithmetic with leap years	6,000	100
water_jugs	Fewest fill, empty and pour steps to measure a volume with two jugs	breadth-first search over jug states	187	100
cryptarithm	Letter-for-digit addition: what number is the sum?	every digit assignment tried; exactly one fits	6,000	100
shortest_route	Shortest road distance between two towns	Dijkstra's algorithm	6,000	100
venn	Two or three overlapping groups: how many like none, or only one	inclusion-exclusion	6,000	100
number_sequence	Next number of a sequence	the rule that built it (one of six kinds)	6,000	100
clock_angle	Smaller angle between the hands of a clock	exact arithmetic	620	100
task_schedule	Shortest time to finish tasks with prerequisites, run in parallel	critical path	6,000	100
ages	One person's age from a sum of ages and a past or future ratio	every pair of ages tried; exactly one fits	6,000	100
digit_count	How many numbers can be made from given digits under a condition	exhaustive count	6,000	100
knight_moves	Fewest knight moves on a small board with forbidden squares	breadth-first search	6,000	100
zebra	Houses in a row: who owns, drinks or lives where, from clues	every arrangement tried; clues added until one fits	6,000	100
balance_scale	Chain two balance-scale equalities into a third	exact ratios	6,000	100

Some families have only a few hundred distinct puzzles at these settings, so they have fewer rows (see Where it falls short). Three examples from the test split:

knights_knaves · On an island, knights always tell the truth and knaves always lie. Juan says: "Prakash is a knight." Carlos says: "Lakshmi and I are different kinds." Lakshmi says: "Carlos and I are the same kind." Prakash says: "Juan and I are different kinds." Who are the knights? Answer with their names in alphabetical order, comma-separated, or 'none'.
Answer: Carlos

water_jugs · You have an empty 5-litre jug and an empty 8-litre jug, and a tap. In one step you can fill a jug completely, empty a jug completely, or pour from one jug into the other until the first is empty or the second is full. What is the smallest number of steps needed to have exactly 1 litres in one of the jugs? Answer with the number only.
Answer: 8

task_schedule · A project has these tasks: task A takes 3 hours; task B takes 5 hours; task C takes 6 hours; task D takes 1 hours and can start only after A is finished; task E takes 5 hours. Any number of tasks can run at the same time. What is the shortest time, in hours, to finish the whole project? Answer with the number only.
Answer: 6

What we checked

• Every answer, twice. The generator computes each answer while it builds the puzzle. A second program, verify.py, written separately and not importing the generator, parses only the question text and solves it again, often with a different method (Floyd-Warshall instead of Dijkstra, listing every grid path instead of dynamic programming, algebra instead of search for ages, counting every number instead of combining digits). It agrees with the published answer on 92,507 of 92,507 puzzles. Run python verify.py data/train.parquet data/test.parquet to repeat this. To test the checker itself, we changed every answer in a 5,087-puzzle sample; it rejected all 5,087.
• One answer per puzzle. For the families where a second solution could exist (knights and knaves, height orders, zebra houses, cryptarithms, ages), both programs search all possibilities and keep a puzzle only if exactly one solution fits. For number sequences, the checker tries six kinds of rule (constant difference, constant second difference, sum of the previous two, multiply-and-add, constant ratio, two interleaved sequences); on every puzzle, all rules that fit the shown terms predict the same next number.
• Exact match works. All answers are short canonical strings: integers (70,403), lists of names (10,437), single names (6,100), weekdays (3,084), the word none (1,763), decimal or whole numbers (clock angles) (720). The longest answer is 47 characters.
• No duplicates, no leaks between splits. Each question text appears once in the whole dataset; no test question appears in train.
• Overlap with public benchmarks. We compared every question with BIG-Bench Hard (all 27 tasks), the Knights and Knaves benchmark and ZebraLogic, which use similar puzzle types. No question matches a benchmark item, and none shares a run of 13 words with one (the standard contamination test). The only shared 8-word runs are stock phrases such as "knights always tell the truth and knaves always lie" and "numbered 1 to 4 from left to right".
• Secret scan. Every file and every text cell was scanned for credentials, keys and email addresses: none found.

Where it falls short

• Templates, not free text. Each family uses one fixed wording. Variety comes from the numbers, names and structure, not the phrasing, so a model can learn the template rather than the skill. Paraphrase the questions if you need robustness to wording.
• Some families are small. At these settings there are only 287 distinct water-jug puzzles (100 test, 187 train) and about 720 clock-angle puzzles; number sequences repeat often for some rule kinds. A model can memorise these families; read their test scores with that in mind.
• Modest and unlabelled difficulty. Puzzles are small (3 to 6 people, grids up to 6 by 6, up to 8 tasks, boards up to 8 by 8). They separate small models but are easy for large ones, and there is no difficulty label. Raise the ranges in the generator for harder puzzles.
• Answers only, no worked solutions. There is no step-by-step reasoning. For supervised fine-tuning you need to write or sample solutions yourself and keep the ones whose final answer matches.
• Sequences assume a simple rule. "Next number" puzzles follow one of six simple rules, and our checker found no puzzle where two of those rules disagree. Some other rule could still fit the shown terms.
• Exact match is strict. is_correct forgives case, spacing, quotes, a final full stop and number formatting, but not other wording ("Lars and Ana" is marked wrong). Ask for the answer in the stated form.
• Look-alike benchmarks. Public benchmarks such as BIG-Bench Hard (date understanding, logical deduction, web of lies), Knights and Knaves and ZebraLogic test similar skills. Training on this data can raise scores there without an equal gain in general reasoning; say so when you report such scores.
• English only. Names come from a list of 197 first names from many cultures.

How it was made

logic_puzzles.py holds one function per family. Each draws random parameters, builds the puzzle text from a template, computes the answer by exhaustive search, breadth-first search, dynamic programming or exact arithmetic, and discards draws that do not give a well-posed puzzle (for example, clues that allow two orders). Each family has its own random stream, seeded by a string and the family name, so the same seed always gives the same puzzles on any machine. make_release.py rebuilds these exact files: the test split first (100 per family, seed udgam-logic-puzzles-v1/test), then the train split (up to 6,000 per family, seed udgam-logic-puzzles-v1/train), skipping any question already used. A family stops early when 3,000 draws in a row give nothing new.

Make more

python logic_puzzles.py --seed my-seed --per-family 1000 --out more.jsonl
python logic_puzzles.py --seed my-seed --per-family 500 --families zebra,cryptarithm --out hard.jsonl
python verify.py more.jsonl          # optional: re-solve every new puzzle independently

Standard library only, Python 3.9 or newer. Use a new seed to get puzzles that are not in this dataset (questions can still repeat by chance in the small families; drop any that appear here if you need a clean held-out set).

Fields

Field	Type	Meaning
id	string	family name and the first 12 hex characters of the SHA-256 of the question
family	string	one of the 17 family names above
question	string	the puzzle, including the form the answer must take
answer	string	the one correct answer, in canonical form
answer_type	string	integer, number, weekday, name, names or none

Intended use and limitations

Use it to train or test reasoning with rewards that a program can check: reinforcement learning with verifiable rewards, rejection sampling, curricula of growing difficulty, or a quick held-out test of small models (the test split). Do not use scores on it alone as evidence of general reasoning ability; the families are narrow and templated.

Licence

The puzzles (the files in data/) are licensed under CC-BY-4.0: reuse them for any purpose, including commercial, with attribution to "Udgam Logic Puzzles by Udgam Labs". The code (logic_puzzles.py, verify.py, make_release.py) is licensed under Apache-2.0 (see LICENSE-CODE).

Citation

@misc{udgamlabs2026logicpuzzles,
  title        = {Udgam Logic Puzzles: 17 families of generated logic puzzles with exactly checkable answers},
  author       = {Prasad, Jitesh K and {Udgam Labs}},
  year         = {2026},
  howpublished = {\url{https://huggingface.co/datasets/udgamlabs/logic-puzzles}}
}

---

About Udgam Labs. Udgam Labs is an independent AI research lab. We work from first principles: before we build, we understand why things work, whether we are training a model, fine-tuning one or applying AI to a new problem. Udgam (उद्गम) is Sanskrit for origin. udgamlabs.com