Sokokan birthmark
The Sokokan birthmark is the informal name of the tattoo that the Sokokan military used to mark colonial prisoners of war and reluctant settlers that had to be relocated during the liberation wars from 7603 to 7643. The tattoo was used on many captured colonial military from several Anarian nations, as well as arrested Anarian settlers unwilling to accept the Sokokan state or leadership.
Background
During the decolonisation process, Sokokan forces often faced resistance by foreign and colonial military. Captured soldiers were be treated by the ICoN standards for prisoners of war, even though in many cases no declaration of war had been issued. Many soldiers were included in prisoner exchange schemes, since the imprisoned military drew on Sokokan resources. However, Sokoku wanted to avoid that able soldiers would return to the battlefields shortly after. Disabling them physically was not an option thanks to the ICoN standards, even though this did occur anyway. The Sokokan military therefore suggested marking all the POW's. In case of being captured again, the marking would be reason enough to execute the soldier on the spot. But a soldier who would return home would have nothing to fear from the Sokokan military.
Application
The first application occurred directly after the liberation of Schlung (Kyusigai) in 7604. Mainly Hellish soldiers got a small tattoo with three purple dots right below the collarbone, of which one would be a skin modification. This method was chosen since it was easy to identify but hardly visible during everyday life and difficult to remove completely by a cover tattoo. The tattoo was also applied to male settlers aged 16 to 60 who were forced to relocate. Later it was also applied to female settlers in the same age bracket. But originally, it was only applied to settlers refusing to repatriate, voluntary repatriates were able to leave without any markings.
The method was hardly used after the liberation of Bowersland (Shaaniaah) since that turnover happened without much military resistance. The same was the case in Tanah Ek (the Auresian colony of Nova Rhegium), Nelyasyat (the Anisoran colony of Aspasia) and Ayatawantin (protectorate of Livaria). But during the liberation of Pakatayu, Neusüdentor and Garis Hati, at was applied on a large scale.
During the Pakatayan secession, a little cross in red ink was used by the rebels, only when the Sokokans entered the battlefield purple ink was used as well, but the cross was taken over as symbol by the liberating forces. The Pakatayan nationalists also applied it to local people fighting in a different (loyalist) faction, but that practice was stopped by the Sokokan army. Even during the Garis Hati conflict, many nationalists were marked by the Sokokan backed federalists, labeling them as collaborators with the (former) Livarian colonisers.
This led to the complicated situation where native Pakatayans and Garishati with the right to reside in Sokoku still had a tattoo mark that could jeopardise their lives. Also, in tropical Sokoku where many people walk around shirtless, this marking is much more visible in every day life. Even wearing a shirt could be seen as a sign of collaboration, which led to tense situations all over those regions.
After the conflict in Garis Hati Gelap ended in the late 7640's, the practice of executing bearers of the markings was outlawed completely. But it could still be a reason to get stopped, apprehended or interrogated without any other reason.
Up to today, there are reported incidents by Anarian visitors or people from Anarian descent (like third generation Auresians and even Nubugaru) getting attacked and marked by overly nationalist and racist individuals and groups. This practice is highly illegal and prosecuted without exception, given the fact that Sokoku is a multi-ethnical state by definition where there is no place for singling out or attacking people with different nationalities or heritages. The punishment for these kind of offences with permanent damage to the victim is 12-18 years imprisonment with labour.
Aftermath
Since the late 7640's the attitude towards the Sokokan birthmark has relaxed quite a lot. As long as foreign citizens can show proper identification that supports legal entry into the country, the marking would not cause any problems. But it took until the early 7680's until the general attitude changed from "guilty until proven innocent" to the other way around. There are even quite a few remaining settlers, currently at quite a high age, that mistakenly have received the marking even though they chose to stay foot under the new regime after the decolonisation.