杀手数独比标准数独难多少？

Row constraint: each row must contain 1–9 exactly once
Column constraint: each column must contain 1–9 exactly once
Box constraint: each 3×3 box must contain 1–9 exactly once

增加了心算约束，但有时能反推更快，整体难度相近或略高。

笼子内数字可以重复吗？

不会，同一笼子的格子在不同行/列/宫，受数独规则约束。

Fill 1–9 · no repeats in rows, columns or boxes · cage sums must match

⚔️ In battle Round {round}/{total} 5:00 0 : 0

Fill the 9×9 grid with digits 1–9 so that no digit repeats in any row, column or 3×3 box.

Cells are grouped into dashed-line "cages"; each cage shows a target sum in its top-left corner
The digits in a cage must add up exactly to its target sum
Digits within a cage cannot repeat (even across rows, columns or boxes)
A cage may span multiple rows, columns or boxes

Start with single-cell cages: the cell equals its target sum
Use combination exclusion: two cells summing to 3 can only be 1+2; summing to 17 can only be 8+9
Cross-analyze rows, columns and boxes: combine standard and cage constraints to narrow candidates
Use the "45 rule": each row/column/box sums to 45, which helps deduce cage boundaries
Note mode: use ✏️ notes to mark each cell's candidates and aid reasoning

Invite a friend for real-time battles! Take turns filling digits — correct moves keep your turn, mistakes pass it. First to finish wins.