重影 Overlapping

两个标准数独共同享有非常大一片区域，这就是重影数独。这种数独通常被用虚线画出，所以许多人会觉得困扰。

Two classic sharing a large part, that's Overlapping. This puzzle is always drawn by dotted lines, so the solver may feel blind (blurred) or fuzzy.

The puzzle is designed by @Sudoku52

赛事频率 较低

部分国内外赛事可能会出现。

要点 外圈的等价性。