What is the SE grade?

SE grade is the difficulty rating produced by Sudoku Explainer, a well-known open solver. It works by finding the hardest technique required to crack a puzzle by pure logic and assigning a number for it. SE grade is the difficulty number from Sudoku Explainer: the higher the grade, the more advanced the logic a puzzle demands. Easy puzzles sit near 1.0–2.0; the hardest monsters reach roughly 11.0 and above. Because the rating is tied to a specific, reproducible solving method, two people grading the same puzzle get the same number — which is exactly why we use it instead of vague labels like "expert".

What does each band mean?

Roughly, the scale climbs from singles-only puzzles to forcing-chain monsters. Each band below links to its own page. SE grade 1 (SE 1.0–2.0): The gentlest puzzles. Solvable end-to-end by spotting naked and hidden singles — no candidate bookkeeping required. SE grade 2 (SE 2.0–3.0): Easy puzzles that still resolve through singles, but you may need to scan more carefully before the next placement appears. SE grade 3 (SE 3.0–5.0): Intermediate. Pairs and locked candidates (pointing/claiming) start to matter — you eliminate candidates rather than place values directly. SE grade 5 (SE 5.0–7.0): Hard. Basic fish (X-Wing) and consistent candidate elimination across rows and columns become the bread and butter. SE grade 7 (SE 7.0–8.5): Expert. Wings (XY-Wing) and larger fish (Swordfish) appear; progress often depends on chaining one elimination into the next. SE grade 8 (SE 8.5–10.0): Diabolical. Simple techniques run dry early; you lean on forcing chains and careful candidate logic to break the puzzle open. SE grade 11 (SE 10.0–12.0): Monster territory. These puzzles have no easy entry point and demand long forcing chains end to end — the home of AI Escargot, Golden Nugget and Platinum Blonde.

Why does Hardest Sudoku use it?

Most Sudoku never gets hard enough — we go all the way up to the hardest; we measure difficulty directly and refine it with data. We also run a controlled experiment comparing SE grade against other difficulty signals using real solver outcomes — so the metric earns its place rather than being assumed.

我們如何評定難度：SE 等級

難度應該被測量，而不是被宣稱。

By The Hardest Sudoku Team · Last updated 2026-06-18

TL;DR

SE 等級（Sudoku Explainer 標準）依謎題強迫你使用的最難邏輯技巧來評分。量表從最簡單謎題的約 1.0，一路到怪物級的大約 11.0 以上。

什麼是 SE 等級？

SE 等級是知名開源解題器 Sudoku Explainer 產出的難度評分。它的原理是找出純靠邏輯破解謎題所需的最難技巧，並據此給出一個數字。 SE 等級是 Sudoku Explainer 給出的難度數值：等級越高,謎題要求的邏輯越高階。簡單謎題在 1.0–2.0 附近,最難的魔王大約在 11.0 以上。

因為這個評分繫於一套具體、可重現的解題方法，兩個人替同一道謎題評分會得到相同的數字 — 這正是我們採用它、而不用「expert」這類模糊標籤的原因。

每個區間代表什麼？

大致上，量表從只需唯一數的謎題一路爬升到強制鏈怪物。下方每個區間都連到自己的頁面。

區間	SE 範圍	需要什麼
SE grade 1	1.0–2.0	The gentlest puzzles. Solvable end-to-end by spotting naked and hidden singles — no candidate bookkeeping required.
SE grade 2	2.0–3.0	Easy puzzles that still resolve through singles, but you may need to scan more carefully before the next placement appears.
SE grade 3	3.0–5.0	Intermediate. Pairs and locked candidates (pointing/claiming) start to matter — you eliminate candidates rather than place values directly.
SE grade 5	5.0–7.0	Hard. Basic fish (X-Wing) and consistent candidate elimination across rows and columns become the bread and butter.
SE grade 7	7.0–8.5	Expert. Wings (XY-Wing) and larger fish (Swordfish) appear; progress often depends on chaining one elimination into the next.
SE grade 8	8.5–10.0	Diabolical. Simple techniques run dry early; you lean on forcing chains and careful candidate logic to break the puzzle open.
SE grade 11	10.0–12.0	Monster territory. These puzzles have no easy entry point and demand long forcing chains end to end — the home of AI Escargot, Golden Nugget and Platinum Blonde.

Hardest Sudoku 為什麼採用它？

大多數數獨永遠不夠難 — 我們一路做到最難,直接測量難度,並用資料打磨。

我們也用真實玩家的解題結果進行對照實驗，把 SE 等級與其他難度訊號互相比較 — 讓這個指標靠實力站穩腳跟，而不是被視為理所當然。

資料來源：Sudoku Explainer（SukakuExplainer）評分引擎；SudokuWiki.org 技巧文件。區間範圍依循慣用的 SE 評分分級。

開始訓練 →