Greetings! I shall treat your question in two key parts: firstly the actual end of the war itself for the Japanese people and government, and the the immediate (about 1945 - 1952) postwar feelings about the US Occupation and the state of domestic politics as a result of the end of the Second World War. The controversies of the war remain a strong topic in Japan and the historical academia to this day. I should note however, that a lot of my sourcing for this response is mostly secondary in nature, so if any contributors have any primary statements from government officials or even civilians regarding the end of the war and the national mood, feel free to add on as well. Let's begin.

The Cherry Blossom Falls

“Despite the best that has been done by everyone--the gallant fighting of our military and naval forces, the diligence and assiduity of out servants of the State and the devoted service of our 100,000,000 people--the war situation has developed not necessarily to Japan's advantage, while the general trends of the world have all turned against her interest.”

- Emperor Hirohito in the "Jewel Voice Broadcast" on August 15th, 1945.

When the Emperor took to the airwaves to announce the Japanese surrender to the Allies, it came like a "bolt from the blue", as many had been kept in the dark about the course of the war, and news of the atomic bombings of Hiroshima and Nagasaki had not yet become nation-wide knowledge. The decision to surrender (according to the Emperor's speech) included the atomic bombings, and the general turning of the war's course against Japan's favour. When the news broke to the public, many were uncertain as to what would happen to Japan in the coming years, and what this surrender meant for the future of them and the country. Others however, claimed that the time had come for Japan's "rebirth", when it could shake off the authoritarian and militaristic "corruption" that had started the war and chart a bold new course in the postwar order. Historian Andrew Gordon on this mix of individual moods:

"Some of his stunned listeners would later recall that August noon as an instant of 'rebirth'. For these people, the surrender was a moment when past experience and values were rendered illegitimate. They decided to chart a totally new course, whether personal, on behalf of a national community, or both. Other listeners, already struggling to find food and shelter in bombed-out cities, fell into a condition of despair and passivity. Still others—especially those in positions of power—resolved to defend the world they knew. Despite the shared national experience of defeat, individual experience varied greatly."

For the military who had kept Japan's war machine turning throughout the long years of war and prior to it, the news of surrender was quite literally fatal. An estimated 350 officers committed suicide in the hours after the Jewel Voice broadcast, although they remained a very minor group in a sea of passive acceptors. The dark legacies of the war's impact played out in the days before the official Japanese surrender onboard the USS Missouri on September 2nd.

Bonfires around Tokyo destroyed any evidence of wartime activities which might be used against the government and military. The planning of official "comfort stations" began on August 18th, and by year's end thousands of women were serving Allied soldiers in "Recreation and Amusement Centers", in an effort to protect the "purity" of the Japanese race from foreign blood (the Occupation authorities outlawed these stations in January 1946, but permitted privately-licensed brothels to continue operations). The government feared that the imperial institutions which had shaped Japan into a modern state would be swept away by the occupying powers, replaced by "state socialism" akin to that which they believed was applied in the USSR (though in this instance, it was the US which they feared would be the revolutionary vanguard).

The late Japanese historian Mikiso Hane, in summarising the impact of the end of the Second World War on Japan, writes:

"[in 1945] all the beliefs and values [the Japanese] had been taught since childhood were shattered...The Japanese people were reduced to ground zero in their moral, intellectual, and spiritual life."

The Occupation and the Legacy of War

When Supreme Commander of the Allied Powers (SCAP) General Douglas MacArthur came ashore to begin the American Occupation of Japan, he represented the two key goals of the occupying forces: demilitarization and democratization. Under his direction, SCAP quickly got to work dismantling the old institutions and laying the foundations for a democratic Japan. The Japanese military was demobilised; around 6.9 million soldiers and civilians in the former possessions of the Japanese Empire (China, Manchuria, Korea, the South Pacific) were sent back home by 1948. The experiences of these returning troops, coming home to a war-ravaged country and families, differed depending on their personal contexts, but in general they shared in the uncertainty of the future that their relatives had felt since the surrender in 1945. Gordon on this matter:

"Repatriates, both civilian and military, often felt out of place back “home,” regarded with a mixture of pity for their poverty and scorn for their role in pursuing what now appeared to have been a hopeless war."

Alongside this major demilitarization effort, SCAP was carrying out a purge of the government, bureaucracy, and businesses for anyone who they believed had played a leading role in the war. Around 200,000 officials, businessmen, and bureaucrats were removed from their posts and barred from ever holding public influence. The question which continued to play on the minds of both the occupying authorities and (to varying extents) the Japanese public however, was the question of the Emperor. Japanese-American historian Noriko Kawamura on this critical question:

"The center of the controversy lies in the question that haunted the Emperor since the days of the Tokyo war trials: if the emperor possessed the power to stop the war on August 15 in 1945, why did he permit the war to start in the first place?"

Some members of the public had already developed deep resent for Hirohito and his calls for their martyrdom at the end of the war. SCAP however, knew that the emperor remained an important figure in Japanese social and political unity. To that end, they did not put the Emperor on trial in the International Military Tribunal for the Far East, shortened simply to the Tokyo Trial (from May 1946 to November 1948). Instead, the Emperor would remain a part of Japan's constitution, but he no longer represented the sovereignty of the state and had no role in politics. SCAP made Hirohito renounce his claim to divinity in 1947, and the new Japanese constitution (promulgated in May 1947), his status was laid out clearly in Article I of Chapter I (which dealt exclusively with "The Emperor"):

"The Emperor shall be the symbol of the State and of the unity of the People, deriving his position from the will of the people with whom resides sovereign power."

Alongside these reforms, the new Constitution also promised a wealth of new rights for the people of Japan. Women gained equal rights in the Constitution, and nowhere was this effect more pronounced than in politics. During the first postwar election in 1946, 13 million women voted for the first time in Japanese history, and elected 39 women to the Diet (the equivalent of a parliament or congress). The Land Reform Law of 1947 also introduced sweeping social changes to Japan. No longer did the rural countryside operate on the "tenant system" of land-lordship, and now farmers could own the land they sowed.

Education-wise, SCAP introduced reforms here as well. They increased the compulsory level of education to the ninth grade, purged professors with suspected political leanings, and outlawed censorship by the Japanese (though the Occupation authorities did engage in censorship itself to a lesser extent). The notorious businesses conglomerates known as the Zaibatsu were decentralised (though not entirely broken up), allowing new opportunities for entrepreneurs and smaller companies to rise in the postwar decades.