At 11 a.m., the Combined Fleet turned west at a distance of 8,500 meters from the enemy fleet and seized the "T" cross.

The Russians had already spotted the whereabouts of the Combined Fleet from the lookout on the shore, and the five cruisers Bayan, Askeld, Deina, Novik, and Baujarin were first attacked.

The Russian warships were the first to open fire at a distance of 8,000 meters, but unfortunately among the five cruisers, the largest caliber guns were the two 200 mm guns on the Bayan, the main guns of the Askold and Deina were 1 5 2 mm, and the main guns of the Novik and Bao Yalin were even only 125 mm.

At this time, Mikasa, the flagship of the Combined Fleet, judged that the distance between the enemy ships was about 7,000 meters, and Heihachiro Togo ordered all the cannons with a caliber of more than 152 mm on the starboard side to open fire, and then the battleships Asahi, Fuji, Yashima, Hatsuse, and Shikishima also opened fire on the approaching Russian ships. The Bayan and the Deina were both shot, but fortunately they were not hit by the main guns of the Japanese warships.

However, these five cruisers bought time for the Far East Fleet, and the remaining five Russian battleships Petropavlovsk, Sevastopor, Postava, Peresvet, and Victory rushed to the battlefield in a column and fired at the Combined Fleet, while the five armored cruisers of the Second Fleet of the Combined Fleet also opened fire to help the battle.

The Mikasa of the Combined Fleet was the first to achieve success, hitting the bow of the Petropavlovsk, followed by the Russian ships Poltava and Victory, and some shells even hit the shore, frightening the people on the shore to flee in all directions.

The Russian ship Novik suddenly left the array, rushed to the combined fleet, and hit a number of Japanese ships in a row at close range, but the main guns of the Novik were too small, so the damage to the Japanese ships was limited, and the Japanese ship Yakumo concentrated its fire on the Novik, and a 2 0 0 mm shell from the main gun hit the middle of the Novik, severely damaging the Novik.

And the Russian ship Ascord swooped down on the third squadron of the combined fleet alone, and was repelled by the concentrated fire of the Chitose and Takasago of the third squadron.

However, at this time, the artillery on the Russian shore batteries also opened fire, giving favorable support to the Russian ships, so the Far East Fleet gradually gained the upper hand, and the Japanese ships were shot one after another, the flagship Mikasa was hit by three bullets, one of which hit the vicinity of Okata, causing seven staff members to be injured, and the military flags on the bridge were all shot down, although the Mikasa immediately raised the spare flag, but it was soon pierced by shells; Fuji was hit by two shots, and 12 people were killed and wounded below the gunner; Shikishima was hit by one bullet, and 17 people below the captain were wounded; Hatsuse was hit by two bullets, and 16 people were killed and wounded below the chief of navigator; and the armored cruiser Azuma, Yakumo, and Iwate were also shot one after another.

Seeing that the situation was not good, Togo Heihachiro hurriedly ordered a retreat, and after withdrawing from the battlefield, after assembling the warships, Togo Heihachiro ordered the fleet to retreat to Asan Bay on the Korean Peninsula to reorganize, and then make plans, and the Qingzhou, which was watching the battle, also bid farewell to the combined fleet and returned to Qingdao.

The Russian ships cheered when they saw the retreat of the combined fleet, and Governor Alesekev also declared the victory of Russia on the grounds of defeating the Japanese fleet, but ordered all warships to retreat to the inner harbor of Arthur and anchor them, under the protection of shore guns, and not to leave the harbor for battle.

In the first battle of the Russo-Japanese War, the Battle of Arthur Mouth ended, and neither warship was sunk; the Russian Far East Fleet fired a total of 2,303 shells (including fortress shells), 11 of which were hit, with a hit rate of 0.48%, 18 killed and 61 wounded; and the Japanese Combined Fleet fired 1,223 shells, 38 hits, with a hit rate of 3.11%, 3 killed and 60 wounded.

Although Japan did not achieve the goal of annihilating or severely inflicting damage on the Russian Far East Fleet, it could be regarded as forcing the Russian fleet to retreat, and therefore it could be regarded as temporarily gaining sea supremacy, so it could not be regarded as completely fruitless.

Togo Heihachiro brought the fleet back to Asan Bay on the Korean Peninsula for repairs because he had received news that the Guasang fleet had sunk two Russian warships at Incheon, and that the landed Japanese troops had occupied Seoul and taken control of the Korean royal family.

It turned out that when the Japanese fleet attacked Lushun, the Japanese army had completed the landing at Incheon Port and attacked Seoul. Rear Admiral Guasheng Waigi sent a letter of war to Colonel Rudnev, the commander of the Varyag: Before noon on the 9th, they must sail out of the port of Incheon and surrender to the Japanese troops, and if they do not leave the port, they will be sunk on the spot, and if the warships of Incheon port and other countries present suffer losses, Russia will be responsible for all the consequences.

Although the captains of Britain, France, and Italy held that fighting in a neutral port violated international law and jointly protested to Kuasang Waiji, they also demanded that the Russian ships take action in a timely manner, either leaving the port or surrendering, and not staying in the port and causing other warships. Colonel Rudnev discussed with the captains of Britain, France and Italy that they could ask the warships of the three countries to accompany the Russian ships to the neutral country. However, the captains of the three countries unanimously refused, and Rudnev was unwilling to surrender without a fight, so he resolutely chose to leave the port to fight.

At 11:30 a.m., the Varyag and the Goryeo pulled anchor and left the port, the officers and men on the British, French, and Italian warships were moved by the courage of the Russian sailors, the Italian warships played the Russian national anthem, the British and French sailors ran to the deck to take off their hats, and the American warships even hung out the signal flag of "good luck."

Seeing the Russian ship leaving the port, the Asami took the lead, first firing at the Russian ship, and the rest of the ships also opened fire, although the Varyag continued to make a curved movement, dodging the shelling of the Japanese ship, and fought back, but in the end, because of being outnumbered, one warship could not match the opponent's 6 ships, not to mention that the Asami was still an armored cruiser, and the combat effectiveness of a single ship was already above the Varyag.

Although the Varyag's fierce counterattack still had some results, destroying the rear bridge of the Asama and the gyroscope of the rear main gun turret, as well as destroying the bridge, mast and rear turret of the Naniwa, and inflicting heavy damage on the Chiyoda, it was also the best of its ability.

The Varyag itself was hit hard, the captain's command station was destroyed, the wheelhouse was blown up, and even Rudnev was wounded by scattered shrapnel. The ship's two range-finding posts and foremast were destroyed, most of the ship's guns were also blown up, and the most serious damage was a 200-mm shell from the Asama below the port side waterline, and a large amount of sea water poured into the ship, and the hull tilted 15 degrees to the port side, killing a total of 30 people and wounding 80 on board. However, the firepower of the Japanese warships was mainly focused on the Varyag, so the other warship, the Koryo, was unscathed.

Seeing that the situation was not good, Rudnev had to lead the warship back to the port of Incheon. Although the Japanese ships stopped shelling when they chased them near the port, Rudnev also knew that his situation was over, so he ordered the Varyag and the Goryeo to sink themselves in the harbor, while the officers and men of the warships were transferred to the warships of Britain, France and Italy, the wounded soldiers were transferred to the hospital on the shore for treatment, and the rest of the soldiers were transferred back to China via Singapore, Hong Kong, and Saigon.

The Japanese advance army that landed on the 9th was stationed in Seoul, although the landing Japanese army was only more than 2,000 people, but Japan originally had a garrison on the Korean Peninsula, although according to the previous agreement between Japan and Russia, both sides were only stationed in Seoul 500, but the Japanese garrison on the Korean Peninsula was not far from Seoul, a day's rapid march arrived, and set off in advance, in addition, just more than one month ago, Japan ordered more than 2,000 soldiers to disguise themselves as civilians, sneaking into Seoul to lurk, so when the advance army arrived in Seoul, the total strength was close to 5,000, although nearly half of the soldiers lacked weaponsHowever, the Japanese army quickly took control of the Korean Imperial Palace, and surrounded the Russian legation and garrison barracks, as well as key areas in the city. Although South Korea had thousands of its own troops in the city, no one dared to go to war with Japan, and could only watch as the Japanese army took control of Seoul.

A few hours later, the Japanese garrison arrived, the strength increased to more than 8,000 people, and brought a large number of weapons, all the soldiers who had been lurking in Seoul received weapons, so they further disarmed the Korean army, took full control of Seoul, and forced the Korean Emperor Yi Hee to issue an order to expel Russian diplomats and garrisons.

By this time, the fighting on the first day of the Russo-Japanese War had completely ended, and Japan had gained a certain advantage by using the tactics of sneak attack without declaring war, but Russia's strength was still there, and the two sides were still generally evenly matched.

Despite the obvious superiority of Russia on the first day of fighting, Russia was still confident in the war, and the report of the night attack on the mouth of Arthur was presented to the Tsar, and Nicholas II was very happy to declare: Now that our division is famous, God and the world are about to abandon the Oriental monkey and smile at us.

On February 9, after the first declaration of war was issued, Tsar Nicholas II and the civil and military officials held a ceremony to pray for victory in the Winter Palace, and the bells of the churches in the city rang to pray for blessings, and the bells rang throughout Petersburg, and students and citizens poured into the streets, chanting "Ula" to gather at the palace. The same was true of Moscow, Kharkov and other places, and the tsar was very pleased with this.

On 10 February, Japan finally issued an edict declaring war, and the same sentiment in the country boiled and the excitement was extraordinary; first, because of the war propaganda in Japan on the battlefield, the majority of the people had actually been looking forward to the war against Russia for a long time; second, on the first day of the battle, Japan was indeed victorious, so in Japan's major cities, every household hung up the national flag and lit up flower-shaped gas lamps, and from morning to night, there was a constant noise. The streets are full of the Battle of Incheon and the Battle of Lushunkou. Signs reading "Celebrating the Victory of the Imperial Navy" were displayed in the shops, and mobile stalls specializing in lanterns were also popped up. Groups such as Keio School, Merchant Marine School, and Wells Fargo Insurance Company took to the streets to hold lantern parades, and people were full of lights and flags, and people were full of voices and stayed up all night.

In Tokyo, a large crowd gathered in front of the General Staff Headquarters, the Admiralty, and the Ministry of Foreign Affairs, chanting Long live the Empire, so much so that the train from Hibiya to Sakurada Gate was impassable.

On the day after the war was declared, a banquet was held in the Imperial Palace attended by the Imperial Family and the courtiers, during which Ito Hirobumi did say that he should not be overly optimistic about the future of the war: "We must not get carried away with our victories just after some victories, and we must keep a good start until we achieve a good result!"