Copenhagen became an important meeting place for many Nordic artists during the war. The contacts with Denmark became very intense 1916-1918 for the artist couple Isaac Grünewald and Sigrid Hjertén. For many of the artists who had spent the early 1910s in France, the Danish capital became a lifeline, a Paris of the Nordics during the cultural isolation of the First World War. Isaac and Sigrid spent the summers of 1917-18 in Denmark. There, on the sunny beaches of Gilleleje in Zealand and on Fanö on the west coast of Southern Jutland, some significant works that are widely famous today, were created. The dramatic "Lightning, Fanö" from 1918 is now in the collection of Norrköpings Konstmuseum, "The green bathing machine, Fanö", hangs in Västerås Konstmuseum, and "Boy with a sailboat" also from 1918, which is presented in this auction, was also painted on the island of Fanö.

"Boy with a sailboat" depicts Iván, six years old, as the main character. He is sitting on the beach waiving a Danish flag. The beholder is invited right into Iván and Isaac's world in this painting, the bold composition with the large foreground figure, leads the viewer into the subject, clearly and naturally. It is easy to feel that you, as an observer, are part of this beach scene together with the Grünewald/Hjertén family. At the water’s edge, sunbathers stroll and children play, the sun sparkles and warms the white Danish sand and you can imagine the scent of summer, sun and holidays. “Boy with flag” is not only an expressive and brilliant painting, it is special as Iván is the main subject, very rare in Isaac's production. For Sigrid, their son was the natural subject of her work in the 1910s, while Isaac often chose to depict the family's surroundings and experiences.

Isaac exhibited “Boy with Flag” at Liljevalchs konsthall in Stockholm in 1918 at the legendary ”Expressionistutställningen” (lot number 82). This exhibition became a fantastic manifestation of Modernism and Expressionism, as well as for the artist couple Isaac Grünewald and Sigrid Hjertén. Isaac participated with 290 artworks and Sigrid with 170, while their friend Leander Engström had to settle for 65 works. The exhibition attracted a lot of attention and audiences were positive.

On the exhibition in Norrköping 2002 the Nya Länstidningen in Lidköping wrote:

“As an art historical event this exhibition is unique with its sixty oil paintings, where most are from private collections and have previously never been on display. All were painted during the 1910s and revolve around the unifying heading "Family life and avant-garde". With a series of self-portraits, home environments, children, interiors and summer days on the beach next to still lifes and Stockholmiana. It is grand, vital and bold with a god-given coloring and a touch that brings to mind not only Matisse but also Kandinsky's lines and Chagall's old Russian villages." (C-J Charpentier, Nya Länstidningen, Lidköping 7 maj 2002)

The stretcher bar is marked in pencil with "TG 25" in connection with the artist’s estates inventory. “TG” is the date letter for 1917.