Mr Kanemaru's resignation came seven weeks after he admitted receiving an illegal donation of pounds 2m from Sagawa Kyubin, a scandal-ridden trucking firm. Public prosecutors subsequently revealed that the 78-year-old godfather of Japanese politics had extensive links with the Inagawa-kai, Tokyo's most powerful yakuza or gangster syndicate.
Initially Mr Kanemaru, who was personally responsible for the appointment of the last four prime ministers in Japan, thought his stature would enable him to ride out the storm of protest over his shady dealings. But when the public prosecutors agreed to fine him only pounds 950 - with no mention of paying back the 'donation' - the protests swelled rapidly.
Mounting criticism from other prosecutors, local assemblies and the general public finally forced Mr Kanemaru to quit. 'I sincerely apologise to the public. It is Shin Kanemaru who was wrong. Kanemaru will withdraw,' he was quoted as saying yesterday.
Mr Kanemaru, whose surname means 'ring of gold', was one of the most expert manipulators of Japan's system of money politics. He entered the Diet, or parliament, in 1954 and became the protege of Kakuei Tanaka, the enormously wealthy former prime minister who was finally felled by the Lockheed scandal in 1976. Working mostly in the construction and telecommunications ministries, Mr Kanemaru built up a formidable power base among companies who funnel money into the LDP in exchange for political favours.
Mr Kanemaru rose to the top of the Takeshita faction, the largest group in the LDP which now contols 110 of the ruling party's 383 parliamentary seats. He never aspired to become prime minister, but wielded immense power behind the scenes in the classic Japanese role of the unseen puppeteer.
A short, crew-cut man with a face like a bulldog and a gruff voice to match, Mr Kanemaru did much of his business in expensive restaurants, well out of the public eye. Although a diabetic, the son of a sake brewer felt more at ease making deals and sealing friendships during drinking bouts than in parliamentary committees.
His departure from the political scene will do little to endanger the LDP's 37-year monopoly on power, but it will leave the Takeshita faction without an obvious leader. The two main contenders now are Ichiro Ozawa, the hand- picked protege of Mr Kanemaru, and Seiroku Kajiyama, who is head of the LDP's Diet Affairs Committee. Neither may be strong enough to take over the faction leadership, which could lead to a split and an internal restructuring of the LDP.
All of this is bad news for Mr Miyazawa, who yesterday expressed 'extreme regret' over the whole affair. Mr Miyazawa has been forced to rely on Mr Kanemaru because his own faction is too weak within the LDP to set its own political agenda. 'Mr Kanemaru was a pillar supporting the Miyazawa administration . . . (His resignation) is a blow to the administration,' said Koichi Kato, the chief government spokesman.
For good measure Mr Miyazawa also pledged to pursue political reform in the wake of the scandal. However, similar pledges were made after the Recruit shares-for-favours scandal in 1989, and Japanese voters have long treated such promises with cynical disbelief.
Mr Kanemaru himself, however, no longer has such concerns as he heads into political retirement. Since the death of his wife last year, the man they called 'the Don' has increasingly shown signs of losing his touch. To fight off loneliness he demanded that otherwise busy and harried politicians and party workers spend hours playing mah-jong with him in his Tokyo residence. And after lying low for several weeks after the scandal broke, Mr Kanemaru suddenly emerged, having paid his token fine, to return to work at his office as if nothing had happened.
Meanwhile, the opposition parties have been deafening in their silence over the affair. An extraordinary session of the Diet is expected to be called on 30 October, but although the Sagawa scandal would seem to be tailor-made for attacks on the government, little more is likely to come out. Sagawa is known to have paid off a number of opposition leaders as well, so the principle of stone-throwing and glass houses will apply.