With his very talented wife Jae Hwa Park they began to produce wine together. They also established a negociant arm of the business, which tends vines for 20 appellations. The domaine itself produces just under 15,000 bottles of wine per year. As time continues, they will eventually stop producing negociant wines and just have domaine bottled wines, as the price of buying grapes is becoming difficult. All the domaine bottled wines are bio-dynamic but not certified. Pests are controlled by the use of bats and there are many plantings of apricot, pear and apple trees around the vineyards.

Covid gave Koji a lot of time to plant these trees. His vineyards in Gevrey and the Hautes Cotes de Nuits see horses used in the vineyard to keep everything as pure and authentic as possible. He will also be introducing baby pigs as they eat the roots of bad plants, an idea he brought with him from Champagne. He has tried with sheep but they are, he feels, too heavy and not right for the soil. In the Haute-Cotes he is experimenting with Pinot Gris, Pinot Blanc and Aliogoté. He loves to dabble. The first commercial vintage will be available in 2027.

Koji also has an interest in Champagne. He developed his love of Champagne with his close friend Jacques Selosse. In 2019 he purchased 1.3 hectares, which will all be certified as biodynamic from the 2023 vintage. His philosophy for producing Champagne is similar to that in Burgundy. Vinification from one plot and fermentation and ageing in barrel. 2022 saw 3 cuvées produced. 2024 saw 1 cuvée produced and 2025 saw 4 cuvées produced – all single vineyards. As he adores Champagne and finds it so easy to drink it really is a love of labour. There is no dosage. He uses natural yeast; his average production is 800 bottles. He is also looking to build a small new cellar in 2026 in Champagne.