In his first major coaching position, head coach of the men's team of HGC, van Ass managed to save the team from degradation and lead them to a championship final in 2007, which was credited to his "opportunistic" style of coaching.[1] HGC lost that game to HC Bloemendaal. Van Ass's HGC reached the final of the Euro Hockey League 2007–08[2] after beating HC Rotterdam in the semi-final, but lost to Uhlenhorster HC in overtime.[3]
In the 2008–2009 season, he coached Jong Oranje (the men's under-21 national team) and was assistant-coach for the Netherlands national field hockey team;[4][5] he returned to coach HGC (which had a disappointing season under Alexander Cox[6]) for the 2009–2010 season.[7] That team reached the final in the national championship,[8] losing again to Bloemendaal, and qualified for the Euro Hockey League 2010–11.[2]
National team
Despite having limited international experience, van Ass was appointed coach of the national team in June 2010, after Michel van den Heuvel [nl] was let go.[8] The appointment came as a surprise:[2] van Ass got the position in favor of Marc Lammers or another international top coach.[8][9]
Olympic selection controversy
Besides not having a coaching certificate,[10][11] van Ass did not select seasoned internationals Taeke Taekema and Teun de Nooijer (nicknamed "T&T"[12]), the country's best known hockey players and icons of the sport.[13] He cut the two from the national selection in January 2012.[14] To justify his choice criticized them in an interview with de Volkskrant a few days later, for which he was accused of character assassination,[10] and he later apologized for his words.[15] After a public backlash Van Ass apologized to T&T at the end of January[16] and took them back in March, his credibility having suffered greatly,[17] but cut them again in July.[10][18]
2012 Olympics
The Dutch team played their opening game in Group B against India, beating them 3–2,[19] and rallied against Belgium in their second match to beat them 3–1, thanks to penalty corner specialist Mink van der Weerden.[20] The team reached the final by demolishing Great Britain 9–2, but lost to Germany, 2–1.