Thank you for your remark kisak - I had a hard time trying to find or prove its Swedish/North European origin. I didn`t do much progress in that topic, but I have found out that the Swedes did like the Cross of Triumph:
What is the correct sword position of looking at a maker`s mark?
Looking at the sword this way (actually it`s on the other side of the blade):
The mark is in this position:
So I have checked what does an inversed cross mean. It`s st. Peter`s Cross - a symbol of humility and unworthiness in comparison to Christ. It makes sense to me - victory but bitter, when you think about. I don`t know if such an interpretation is possible, but it`s interesting.