From Tatiana’s TOMATObase:
- Russian origin.
- Seeds from Soren Holt of Frosamlerne (Danish seed savers) who received it from the Sviatova family in Siberia. Originated in Sludjanka at the shores of Lake Bajkal in Siberia where it is grown outdoors. It is not clear whether it was developed by Katerina Konovna Sviatova (Katja) herself or if it is an old Russian commercial variety.
- 2 different variations are available in North America via the Seed Savers Yearbook - one is the large pink as described here, and another is a small to medium red. It is not clear whether these are different tomatoes or a segregation of the original Katja tomato that may not have been 100% stable.
I was able to find Søren's own description of it (translated from danish):
"Rosa beefsteak. Determinante growth. It is a variety that I have been sent from my family in Siberia. It comes from aunt Katja, who has a Datcha (summerhouse) in Sludjanka on the shores of Lake Baikal. It's origin is unknown, but it is probably a Soviet commercial variety she has maintained, it can also be her own spontaneous-variety from a mutation or crossover. In that part of Siberia, they experience that the tomatoes crosses quite a bit.
They plant them out in the open, and stake them to a approx. 80 cm. stick. It thrives well outside the greenhouse, and ripen just as early as in the greenhouse. However, the taste is far better when it grows in a greenhouse. They are sweet and juicy. The only drawback is that it can be finished before the season is over, so it must be supplemented by later varieties. It is a tomato I can strongly recommend. If I had to grow only one variety, it would be this one."