Logic Masters Deutschland e.V.

This is my first attempt at a quattroquadri puzzle.

Standard quattroquadri rules: Place the all digits 1-9 into each 3x3 region, such that no digit repeats in a row or column.

XV: Digits in cells separated by an X must sum to 10; digits in cells separated by a V must sum to 5. ALL Xs and Vs are given, so there is a NEGATIVE CONSTRAINT.

Arrows: Digits on a blue/grey arrow must sum to the value in the attached blue/grey bulb.

Counting Circles: Digits in black circles say how many times that digit appears in a black circle in the grid.