TSTOS series and Ehasa

The Battlegroup series is the largest and longest airsoft event series organized by the Finnish Ehasa Association. The series has been organized since 2016 in the Ilveskallio training area in Hattula, Hämeenlinna.

Tstos 18


TSTOS 18 is the third part of the game series, which is also the longest, over 90 hours, and is expected to have 800-1000 participants. The story continues with the control of the RSV device and its development with gold, which is mined from the Ilveskallion bedrock. For this reason, there are several different smaller factions in the region that operate between Uusimaa and Pirkanmaa.

Tstos 17


TSTOS 17 was attended by more than 700 people and it was a day longer than the earlier event. TSTOS 17 continued the old story that, after the destruction of the hidden armor halls, factions competed against the management of fuel supplies and investigated the mysteriousRSV device by solving various codes.

Pictures of the event

Tstos Parola / Tstos 16


TSTOS Parola was the first event organized by Ehasa that lasted over the weekend and was attended by more than 600 people. TSTOS Parola started the current game story where Finland is divided into two fighting parties, Uusimaa and Pirkanmaa, who fought over the control of Ilveskallio hidden armor halls. In addition, the situation was confused by the independent Ålands special forces and the United Nations.

Pictures of the event

TSTOS game series

TSTOS events are attended by nearly a thousand players from Finland and abroad all the way to Brazil. The event takes several days, without the game situation being interrupted separately. The main faction bases are calmed down at night to ensure a sufficient rest. Tens of different vehicles, such as tanks, off-road vehicles, SUVs and ATVs, participate in a single TSTOS event. Most of the vehicles are involved in the game and can be destroyed by separate anti-tank weapons. Comparing to similar events in the world, we are the longest event with the Swedish Berget-series. In the number of participants, we represent the biggest airsoft events in Europe.

The content of the events

What happens in the event takes place in an imaginary world with mostly imaginary factions and nations created by the game masters. Our goal is to combine military simulation, standard airsoft, and thrilling features, creating a very cinematic and overall realistic experience. Players may appear in the event as soldiers of the fighting parties, civilians, and different in-game organizations and groups. Depending on the faction, players will be led by volunteered team and platoon leaders, company commanders and battalion commanders.


Ehasa ry works closely with the Hattula section of National Defense Training Association(MPK) and the assistant organizers involved in the organization are part of MPK's "Basics of organizing a exercise part 2" course. The purpose of the course is to learn the organization of public events, which is comparable, for example, with the organizing of large military exercises. Participants in the course will benefit most from the training paid by Ehasa, such as the Finnish red cross First Aid Card and the Community Service Officer card.

Recently, Ehasa has started to cooperate with the Finnish Reservist Sports Federation.


  • The number of participants has risen by about a hundred annually.
    • 2016 +600
    • 2017 +700
    • 2018 +800-1000?
  • Over 40 player and organization owned vehicles as part of the game.
  • Average age of participants: 27 years.
  • +95% of participants are men, but women are more than welcome to our event.
  • 35% of participants have taken part one or more events in abroad so our event is good start to take part similiar events outside of Finland.
  • +45% of participants have served mandatory service for 347/365 days in Finnish Defence Forces. Overall +60% have served in FDF.
  • Around 20% of participants are active reservist or have shooting/hunting hobby.
  • Participants in 2017 from five European countries, among others Sweden and Lithuania.
  • The duration of the longest event is over 90 hours.
  • Ehasa members: 20 pcs.
  • In addition to the members of the Ehasa, there are assistants annually about 20.

Media visibility


Ehasa or the old East Helsinki Airsoft Association is originally a registered association established in Helsinki, whose task was to organize local airsoft weekend games. Since 2010, we have moved to organize ever-growing events,which we have now organized over 30 times in different parts of South and Central Finland.

We are currently organizing the biggest events in Finland, and many enthusiasts of the sport know the reputation of Ehasa and have participated at least in one of our events.The cornerstone of our association is fast and active customer service, feedback-responsive event development, and ambition to always make events better for all of our participants.

To facilitate our operations, we have created many different programs and services, such as a kuulaportti -registration system and status.ehasa.org flag tracking system, which both are also partly available to other airsoft event organizers.

Our association consists of 20 young adults about 20-30 years of age,with the know-how of different fields and the desire and vision to take Finnish airsoft events forward.We also have few active military reserve members and as a result of that we have ended up in cooperation with different reserve associations.

Our regular events can be organized by ourselves, but the TSTOS game series also requires assistance from non-members. For this reason, we have a separate recruitment page, through which you can apply as an assistant to our TSTOS and other game series.