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.

难度是这样评定的：SE 等级

难度应该被测量，而不是被宣称。

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

TL;DR

SE 等级（Sudoku Explainer 标准）依据谜题迫使你使用的最难逻辑技巧来评定难度。刻度从最简单谜题的约 1.0 一路延伸到魔王级的约 11.0 以上。

什么是 SE 等级？

SE 等级是知名开源求解器 Sudoku Explainer 给出的难度评级。它的原理是找出纯靠逻辑破解一道谜题所需的最难技巧，并据此赋予一个数值。 SE 等级是 Sudoku Explainer 给出的难度数值：等级越高，谜题要求的逻辑越高级。简单谜题在 1.0–2.0 附近，最难的魔王大约在 11.0 以上。

由于评级绑定在一套具体且可复现的解题方法上，两个人给同一道谜题评级会得到同一个数字 — 这正是我们用它取代 “expert” 之类模糊标签的原因。

每个档位是什么意思？

大体上，刻度从只用唯一数就能解开的谜题，一路攀升到强制链魔王。下面每个档位都链接到各自的页面。

档位	SE 范围	需要什么
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 为什么用它？

大多数数独永远不够难 — 我们一路做到最难，直接测量难度，并用数据打磨。

我们还在进行一项对照实验，用真实玩家的解题结果把 SE 等级与其他难度信号做比较 — 让这个指标靠实力赢得位置，而不是被想当然地采用。

来源：Sudoku Explainer（SukakuExplainer）评级引擎；SudokuWiki.org 技巧文档。档位范围遵循惯用的 SE 评级分层。

开始训练 →