An educational system (double curtain education) developed in the early 1960s by the American viticulture expert Dr. Nelson Shaulis (1913-2000) at Cornell University (Geneva, New York State). It belongs to the large group of so-called cordon education systems. Originally it was created especially for the Concord grape variety to enable mechanical grape harvesting. The vines are trained on a high T-shaped framework (also V-shaped). The distance between the vine rows is about three metres. The young shoots are divided to the left and right and the foliage is directed onto two fold-down wire frames.
By folding down, the plant grows downwards, which inhibits the growth force and improves the incidence of light. The system has gained little importance in the USA and Australia; in Europe it has not even proved itself. One variant is the duplex system developed in California, which allows largely mechanical harvesting. Only the grape-bearing fruit rods (not the leaf shoots) are attached to a wire. The duplex system developed in France Lyra education is also similar, but with this one the shoots are upward directed. See also under Form of upbringing (systems) and Vineyard care (activities).