While he drew the advertising and posters in the film world, the 2nd world War was coming, so he came back to Phyarpon Township and enlisted in the “ Burma Defence Army ’’ (B.D.A).

At this period the youth organized the Burma Defence Army secretively to resist the intruded Japanese. Saya U San Hlaing had volunteered as a patriot like other youths, therefore he put down the brush and held the weapon to attack the Japanese. So he joined the army.

He gave his name to the list of the Leader Bo Taunt Htain, Burma Independent Army, (B.I.A), Phyarpon. Besides, he had done the work as the volunteer in the guard force of the Town.

In 1943 he entered into the outpost, Ministry of Defence Yangon and then transferred to No.1 Mingalardon Training Battalion (1). Then he had been provided the comrade of B.D.A. He served as an instructor to teach military science to the new recruits. His salary was 30 Kyats per month. The Leader of the battery was Bo Aung So and the leader of the platoon was Bo Mya Din, both were in the Battery (3).

From that he was included in the reorganization guerilla battalion (1001), Minhla Sitthu Division under the battalion commander Aung Din (or) Bo Htin Kyaw. On 1st May 1995, they participated in the battle to take possession of the Town, besides in the battles of Sittaung River valley. The leader was Japanese commander “Sakurein’’, and succeeded.

Then together with Gunkhas and English soldiers, the fascist Japanese retreated from Htantabin to the Sittaung Valley battlefield, when Japan Division (33), Division (28) and navy through Bago Yoma and withdrew the Sittaung River, he participated in battalion (106) and attacked at the regions such as Sittaung, Thamanthaung, Myabago, Ngehtwaysoat, Htun Kon, Weggyi, Luaha, Matithalin, Saypale, Yelae (Myanmar village), Yelae (Kayin village), Wettoo, Paunglung, Myitngal and Nathrakwin.

At that time the leader of the platoon was Bo Tun Yi (Myin Mu) and U San Hlaing had three stars (pips) and they moved from Sittaung region to Penwegone region, Khinthar, Khint Khant Land and Taungthonelone.

In 1945, he heard about the beginning of the reorganization of the Burma Independent Army (B.I.A) and he had a chance to fix the medal, which was composed of a green background and one silver line over it.

Then he came back to Phyapon in this period Sayargyi U Ngwe Gaing headed and opened the Department of military art in the Yangon Ministry of Defence. They invited the painters to move to the military art department. Although they called U San Hlaing to their department he argued it, because he was more interested in fighting for the Independence.

After he painted in Phyapon for one and a half months, he came back to Yangon and entered back into the army. At that time comrades and officers were reorganization according to the Gandi Treaty. So he entered into the public Comrade Department, which was led by Bogyoke Aung San and he served as the General Secretary of Phyapon District.

After the death of Bogyoke Aung San and the martyrs by the murders, the other placed order by Bo Min Kaung, the battalion –commander of the suppression of insurgents (2) and he was promoted to the corporal sergeant post, nearly the period of announcement of Independence news he had left from the army and he tried to study back the painting art after he served over one year as the corporal Sergeant post. Sayargyi U San Hlaing’s emotional talk while he was in the Army.

“ While I was enlisted in the Army engage in revolution. To fight against the squatters, this was his aim. He had no benefit or any hope. At that time, we must hold the weapon. Sometimes we meet with difficulties in our country, our nationality and religion and our culture and obsession to observe the rules. But he could not sometimes.

When we went up to the “ Kyaikhtiyo Pagoda wearing shoes, my mind did not dare as Buddhist. But we have done it because it was an emergency case. That was difficult for us.

On the battlefield, we have no sleeping time day and night. We were very tired and often hungry.

At times we did not have a chance to eat our square –meal. But we did not care because of our aim to fight against the Squatter. I enlisted in B.D.A for my patriot by myself.

I was awarded the “ Humongous Second Grade ’’ ( The most outstanding award ) by the President of the Union of Myanmar in person in Serial No.452 under the record of engaging in fighting against the colonialists from the very beginning up to the independence with strong patriotism.

In 1942 when the revolution began in Rakhine Stage, the two monks, U Pyinnyar Thiha and U Saindar participated in it. U Saindar was a communist and although I believe in Buddhism on the other hand I like Maxims too.

But nevertheless, the main aim was Freedom.

Sayargyi U San Hlaing talked about his life. It was very interesting to listen to the recollections of Sayargyi about his joining the B.D.A to fight out the enemies. As he was explaining in detail, word by word, so could see the scenes vividly.