On the evening of the 14 January 1944 a special Japanese Army Reconnaissance party left Koepang, in Timor on board a 25 ton fishing vessel called "Hiyoshi Maru". The party included:-

Lieutenant Susuhiko Mizuno
Sergeant Morita
Sergeant Furuhashi
Lance Corporal Kazuo Ito (radio operator)
6 sailors
15 Timorese (used as decoys)

Their orders from the 19th Army Headquarters on Ambon Island were to land on the north west shores of Western Australia. They were from the special "Matsu Kikan" (Pine-tree) secret agency which was commanded by Captain Masayoshi Yamamoto. They were all graduates of the Nakano Intelligence School. Their mission was undertaken at the request of the Japanese Navy to verify intelligence received from Navy sources that the United States Navy was building a Naval base at Admiralty Gulf. 

Lieutenant Susuhiko Mizuno's role was to:-

- look at the possibility of landing in Australia
- Investigate the location for a landing place
- look for the existence of an military establishments

They encountered a large storm and heavy seas and had to turn back to Koepang on the morning of the 15 January 1944. They departed again on the evening of 16 January 1944. 

The "Hiyoshi Maru" was given air cover for part of the voyage by a single Type 99 light bomber from the 7th Air Division based at Kendari. It was piloted by Staff Sergeant H. Aonuma with Hachiro Akai as Co-pilot. On 16 January 1944, the aircraft was heading directly for Cartier Islet when it saw an Allied submarine heading in the direction of the "Hiyoshi Maru". The submarine saw the Japanese aircraft approaching and immediately began to dive. The Japanese aircraft only managed to fire two bursts of its machine guns at the submarine as it submerged. The tracer bullets could be seen hitting the submarine. The Japs then dropped their six 50 kg bombs on the submarine. They then circled around the area three or four times to determine if they had hit it with one of their bombs. They suspected the submarine may have sustained some damage.

The aircraft continued south flying low to avoid the Allied radar sites situated along this remote coastline. They sighted the "Hiyoshi Maru" and continued south to try to locate Cartier Islet. When they could not find it they headed to the west. They then  eventually located Cartier Islet.

At 9 am on 17 January 1944 the "Hiyoshi Maru" reached East Island which is actually a coral reef which is only visible at low tide. They reached Browse Island at about 10 am on 18 January 1944. They landed on the island where they found the ruins of a watch house. 

They stayed on Browse Island for about 3 hours. This was to time their arrival on the nearby Australian mainland. The left the island at 1 pm on 18 January and the next morning through a morning mist they entered an inlet on the West Australian coast. They spotted some white smoke rising from a mountain on the mainland east of their location. They anchored by the shore at about 10 am on 19 January 1944. The landscape in that area consisted of many red colored rocks. They camouflaged the ship with tree branches and ate dried biscuits for lunch.