Dear Rabble,
As my username suggests, I am clan Donnachaidh/Robertson. I have just one kilt (8 yards heavyweight wool) in my clan tartan - Robertson. Having reviewed my wardrobe, my kilt is showing signs of wear and tear, and due to vast quantities of ale over the years, my 'waist' (read 'pot belly') has gotten bigger. I am in need of a replacement kilt. I have looked on many websites, found a price that suits my pocket, and have decided to have a new kilt made to measure. Ok - so far, so good.

I have come across a phenomenon that I do not understand.

My 'old kilt' has about 4 and a half big red squares from top to bottom.
I have seen kilts purporting to be Robertson (red) tartan, and they have varying numbers of big red squares - 5, 6, 7,.....? from top to bottom. i.e. a smaller 'check' tartan.

Could anyone be so kind as to explain why this is? Are they variations of my tartan? Modern versions, cheap imports, fakes? (I don't think they are extra long kilts!)

Many thanks in advance.