The "Four Days of the Yser" is an international march, organized by the Belgian Defence. This annual 'military exercise' is open to civilians and military, Belgians as well as foreigners.

• to strengthen the bond between Defense and the Society by bringing the military and the civilians together during a common sports effort

• to respectfully commemorate the casualties of both World Wars, particularly those who fell on the battlefields of the Westhoek during the First World War

• to introduce the hikers to the historical and tourist values of the Westhoek in a pleasant way

Organizing the four-day walk is a mission for the Artillery Battalion. This Battalion, stationed at the Belgian Northsea-seaside, gets assistance from the Competentiecentrum SteunMaterieel en Producten, an ordnance competence centre in Ieper (Ypres). The organization runs in close cooperation with cities of Koksijde, Nieuwpoort, Diksmuide, Poperinge and Ieper (Ypres).

Every year, the Executive Committee of the Four Days of the Yser offers four days of hiking pleasure to the walkers during the first complete week following 15 August (Assumption is an official holiday in Belgium). The secretariat determines and draws a 8, 16, 24 and a 32 km route for every day. A number of rules, according to a fixed pattern, are strictly observed (exeptions are always possible) :

• the opening ceremony, and the arrival of the first day always take place in Koksijde-Oostduinkerke, the municipality that holds the roots of the Four Days

• it is our ambition that the route of the first day will always include a passage on the territory of Nieuwpoort, the last city on the Western Front of the First World War. Exeptions are not exluded

• the arrival of the last day, the closing ceremony + parade of all participants and the start of one of the four days (usually of the fourth day) will always take place in the city of Ieper (Ypres), the legendary symbol of W.W. I

• the remaining arrival places are located in the other 'Western Front' cities Poperinge and Diksmuide