Changelog

Version history

1. 0.3.02026-09-06
   • Rule changeEvery puzzle is now checked at build time to be solvable by logic to the last cell, and only those go out. Four out of five expert boards used to leave you guessing partway
   • ChangedA puzzle number opens a different board than before, because the way boards are built changed
   • AddedA progress bar appears while a board is being built. It shows up only when the search runs long, and says how many boards have been checked
   • FixedThe screen no longer freezes while a board is built. You can pick another difficulty mid-search
   • ChangedMuted text is darker. Labels, the status line and notes went from 4.1:1 contrast to 5.1:1
   • FixedThe “OFF” pill on the notes button is readable. White on grey measured 2.05:1
   • ChangedThe count of remaining digits moved below the number, not beside it. On phones the small “5” next to “1” read as 15
   • ChangedBoard digits are slightly larger, matched by measuring letter heights against the site we compare with
   • ChangedMistakes, time and the buttons split the row above the board into equal thirds. The clock and the buttons used to sit on top of each other
   • ChangedThe site is called Play Sudoku, at play-sudoku.co
   • FixedAbout, privacy, terms and the changelog now exist in each language. Following them from the English pages no longer drops you into Korean
2. 0.2.02026-09-05
   • AddedThe board now carries four readouts: score, difficulty, mistakes and time. The icon beside the clock pauses
   • AddedA digit that does not match the answer turns red on the spot and is counted, up to three. At three the board stops
   • AddedSettings arrived. Highlight the row, column and box; highlight the same digit; flag duplicates; count mistakes; quick entry; auto notes — six switches
   • AddedYour score climbs as you play: difficulty multiplier × (10 per correct cell − 20 per mistake − 30 per hint), plus a time bonus once you finish
   • ChangedEight buttons became four. Undo, erase, notes and hint stay on the row; quick entry and auto notes moved into settings
   • ChangedNew games are picked from a list that opens under the button. The warning that your progress will be lost can be turned off with “don't ask again”
   • ChangedFinishing a puzzle opens a panel with the difficulty, your time and your score
   • ChangedThe hint icon carries the number you have left
   • ChangedThe board and its digits are larger — up to 500px wide, with 42px digits on the number pad, so your eyes work less
   • ChangedThe selected cell is light blue and its row, column and box are a pale blue-grey. Where you are looking is now obvious at a glance
   • ChangedThe thick lines that split the 3×3 boxes and the thin ones between cells are different colours, so the nine blocks read first
   • ChangedThe accent colour moved from magenta to blue, and the header is now white
   • ChangedDigits are set in Roboto. Korean is drawn in the device's own font, so nothing heavy is downloaded
   • ChangedDifficulty is chosen from the row above the board. “New game” opens a list attached to the button
   • AddedA rules page arrived, covering the three rules and what row, column, box, clue and candidate mean
   • AddedAn awards page arrived. Twelve badges come from finishing each difficulty, from puzzle counts, from day streaks and from your times
   • AddedA daily-challenge calendar arrived. It shows which days you solved, month by month, and a past date opens that day's puzzle
   • ChangedDays you solved the daily puzzle are kept for 400 days. Only the last one used to survive, so the calendar lit a single square
   • ChangedThere is no leaderboard on awards or the daily challenge. Nothing is sent to a server, so there is nothing to compare against
   • AddedA tournament arrived. Three boards — medium, hard and expert — and everyone who comes that week plays the same three
   • AddedFinishing a tournament board records your time, and finishing all three shows the total. A replay only replaces the record if it was faster
   • ChangedThe header and the tab row beneath it became one row. Forty vertical pixels went away and the board rose by that much
   • ChangedOn narrow screens the menu folds into a hamburger. It closes on Esc or a tap outside, so it never sits over the board
   • ChangedThe board is 20px larger on phones. The side margins were narrowed to use more of the screen
   • ChangedUndo, erase, notes and hint have wider touch targets on phones. The icons are the same size; only the misses went away
   • Added“How to solve” gained a table that finds a technique from what you are seeing, so it is usable at the moment you are stuck
   • Added“Rules” now names the four things beginners actually trip on: guessing, skipping notes, reading only cells, and forgetting the box
   • AddedThe daily-challenge page now says that solving a past date neither fills the calendar nor extends a streak. That was written nowhere before
   • AddedThe tournament page now gives an order for the three boards and three ways to cut your time
   • AddedThe awards page explains how the time badges are earned: they look at your best time, so one good run lights them for good
   • FixedLeaving a finished board and coming back gives you a fresh puzzle at the same difficulty, not the completed one
   • FixedArriving on a link with a puzzle number and then picking a new game keeps the new one. A refresh used to snap back to the first puzzle
   • AddedA puzzle you have already solved is not handed to you again. This browser remembers the last 300
   • FixedA hint is counted only when you place it. Opening one and closing it with “leave it” costs nothing
   • ChangedHints come in three pages — where to look, why, then what to place — so the answer does not arrive first
   • FixedPlacing a digit or undoing closes an open hint. An explanation that no longer matched the board used to stay on screen
   • FixedThe hint card opens over the number pad. On small screens it sat below the fold, so pressing hint looked like it did nothing
   • ChangedOpening a hint dims the board and leaves only the cells it points at lit. Where to look now arrives through the eyes
   • ChangedThe difficulty row is labelled “Difficulty:” and the current one wears a blue pill. Colour alone was hard to spot
   • ChangedOn wide screens the header and footer line up with the board's width instead of spreading to the edges of the screen
   • ChangedType is bigger: hint titles 13→19px, hint text and the note under the board 13→15px, the clock 15→16px
   • Changed“How to solve” moved from the header to the footer. The header keeps only the ways back to the game
   • AddedThe tournament runs monthly. A hundred players including you, with the time left counting down by the second
   • AddedTournament points come from every board you finish that month, not only the three set boards
   • ChangedThe players on the leaderboard are invented by this browser. The top 1% is paced at about one puzzle an hour
   • ChangedThe “redo · check · restart · settings” row under the board is gone. Restart lives inside “new game”, settings under the gear beside the clock
   • ChangedAll hundred scores are visible on the leaderboard, and opening it scrolls to your place
   • ChangedBetween 20% and 40% of entrants do not show up in a given month — people who register and never come are left as they are
   • AddedWhere you placed in past tournaments is kept. The awards page groups them by year and month
   • ChangedThree mistakes ends the game and sends you to a new board; there is no second chance. A limit you can undo is not a limit
   • ChangedPlayers carry names. They are handles like Comet and Lumen, never people's names
   • AddedThe time left sits beside “Daily” and “Tournament” in the menu — midnight, and the last night of the month
   • ChangedThe tournament moved from weekly to monthly. Weekly meant that someone arriving on a Sunday saw a contest a few hours long
   • AddedHovering an icon button says what it does: undo, erase, notes, hint, pause and settings
   • FixedThe settings, erase and undo icons were redrawn. Settings looked like a sun, and the eraser's underline had come loose
3. 0.1.02026-09-05
   • AddedSudoku opened. Four difficulties, no login, nothing to install
   • AddedHints give the reasoning instead of the answer — “7 fits only here in row 3” — and light the cells the reasoning rests on
   • AddedPlacing a digit clears it from the notes in the same row, column and box. You no longer erase twenty cells by hand
   • AddedUndo and redo go all the way back, one note at a time
   • AddedClose the tab and the puzzle is still there. It is kept in the browser and never sent to a server
   • AddedOn wide screens the number pad and hints sit beside the board, so reading a hint costs no scrolling
   • AddedTurn on “quick entry” to pick a digit once and then tap cells. Filling many cells with one digit stops being a round trip
   • AddedPause and restart arrived. Pausing covers the board — stopping the clock while the answer stays visible is not a pause
   • AddedA record panel sits under the board: best time and count per difficulty, and how many days in a row you have played
   • AddedAn “expert” difficulty arrived. The median backtrack count rises from 109 at “very hard” to 824
   • FixedDifficulty labels were corrected. Some boards were graded up merely for having many empty cells
   • Changed“Fill notes” became “auto notes”. Left on, it recomputes the candidates after every move
   • FixedCandidates removed by a hint no longer come back with auto notes. Progress like “the 4 in this box is on this line only” used to vanish every move
   • AddedEvery puzzle carries a number. Pass on the number or the link and someone else plays the same board
   • AddedPrinting gives you the board and its number, so you can solve on paper and reopen it by number
   • AddedHint techniques went from five to nine, adding hidden pairs, naked triples, hidden triples and X-Wing
   • FixedThe next hint remembers the candidates already removed. The same elimination used to be offered again and again
   • Rule changeDifficulty is now the hardest technique the puzzle needs. The label says what it asks of you — “Medium · up to hidden singles”
   • Rule changeUp to “very hard”, following the hints reaches the end. “Expert” boards need more than the nine techniques
   • AddedA daily puzzle arrived. The date is the puzzle number, so everyone plays the same board that day
   • ChangedThe day streak counts the daily puzzle only. A number you build by tapping one easy board a day means nothing
   • AddedThe site opens without a connection. One visit and the browser keeps the game and the writing
   • AddedEvery technique has its own page, so arriving from a search like “sudoku X-Wing” gives you the worked sentences
   • AddedEach technique page links four boards where that technique is the decisive one, to play right after reading
   • AddedHint techniques went from nine to twelve, adding Y-Wing, simple colouring and Swordfish
   • ChangedSome “expert” boards can now be explained to the end. Every one of them used to fall outside our techniques
   • Changed“Hidden single” was split into scanning a box and scanning a line. The logic is the same; the work your eyes do is not
   • FixedDifficulty labels were corrected. Some boards said “up to pointing pairs” while actually needing naked triples