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. Now 2020 we are continueing in the new area, Padasjoki.

Tstos 20


TSTOS 20 osallistui yli 500 ihmistä. Tarina keskittyi Pirkanmaan ja Uudenmaan taisteluihin YK:n yrittäessä turvata rauhaa siviiliväestön keskuudessa. Tapahtuman aikana uusi esiteltiin uusi osapuoli Hölböcorp, jonka alueelle tuoma ohjus räjähti tuhoten Pirkanmaan ja Uudenmaan taistelevat joukot.

Kuvat Videot

Tstos 19


TSTOS 19 was attended by more than 700 people and was again the longest airsoft-event in Finland, lasting more than 90 hours. In the story, the RSV device was once again controlled by various factions and eventually RSV left the area. Rumor has it that the RSV was completely destroyed and will not be seen in future.

Kuvat Videot

Tstos 18


TSTOS 18 was the third part of the game series and there were over 800 participants fighting over 90 hours. In the event bouth main factions strived to control RSV device. Meanwhile Remedtech developed the device further with the gold mined from gold mines in the Ilveskallio area. Because of the RSV developement, a certain foreign intelligence service was also operating in the area trough Blue rose as a covert operation. Again, the village and some of the gold reserver were dominated by the mafia in co-operation with the Ilveskallio National Guard organization.

Kuvat Videot

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.

Kuvat Videot

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.

Kuvat Videot

TSTOS game series

TSTOS events have generally been 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 other associations and federations (MPK and Reserve Sports Association), municipalities (Padasjoki and Hämeenlinna) and authorities (Defense Forces, Police, Rescue Service and Finnish Forest Administration). In 2016-2018 we organized cources in co-operation with the National Defense Training Association(MPK). The assistant organizers from MPK were involved in the Ehasa organization as a part of MPK's "Basics of organizing a exercise part 2" course. The purpose of the course was to learn the organization of public events, which is comparable, for example, organizing of large military exercises. Participants in the course did benefit most from the training paid by Ehasa, such as the Finnish red cross First Aid Card and the Community Service Officer card. In 2019, we organized the first Tstos event in Padasjoki and also the first event without MPK cooperation. The challenges were, among other things, the large event area and its high use rate, as well as the lack of organizer presonnel. In 2021 we will continue in the same way, but again without MPK cooperation.


  • The number of participants has risen by about a hundred annually.
    • 2016 +600
    • 2017 +700
    • 2018 +800
    • 2019 +700
    • 2020 +500 COVID
    • 2021 ?
  • 54 player and organization owned vehicles as part of the game (2020).
  • Average age of participants: 30 years (2020).
  • +95% of participants are men (2018), but women are more than welcome to our event.
  • 35% of participants have taken part one or more events in abroad (2018) 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 (2018).
  • Around 20% of participants are active reservist or have shooting/hunting hobby (2018).
  • Participants have been from Sweden, Norway, Estonia, Latvia, Lithuania, England and also from Brazil (2018-2020).
  • The duration of the longest event is over 90 hours.
  • Ehasa members: 25 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.