As Hirofumi Nakasone tells it, he is running for the upper house of parliament from hilly Gumma prefecture northwest of Tokyo because of pleas from the local political elders. "It's only Hirofumi who can win it," he recalls them as saying in strategy sessions before his nomination.

Campaign workers at the busy headquarters of his rival, Hiroichi Fukuda, scoff at this explanation. They say Nakasone is in the race mainly because of phone calls, speeches, money and other forms of support and pressure from his powerful father, Prime Minister Yasuhiro Nakasone.

Fukuda's supporters can do only so much with the nepotism charge, however. Their own man has an elder brother named Takeo Fukuda, a former prime minister of Japan. Hiroichi calls Takeo "the great central pillar on which I heavily depend."

Modern Japan is often viewed from abroad as a society built on merit and seniority. But in many areas, politics in particular, how far you get can depend to a great degree on your blood and family name.

Of the 830 candidates who in the July 6 general election will seek seats in the lower house of the Diet, or parliament, about 210 have a father, a brother, an in-law, a spouse or a relative who was a politician, researchers for the Mainichi Shimbun newspaper found. In the United States, such a pattern of kinship is rarer.

The young Nakasone's candidacy has attracted attention to this pattern, but it is nothing new.

In the 1950s, Japan had a prime minister named Ichiro Hatoyama. His father had been speaker of the Diet's lower house. Hatoyama's son now is a veteran of the upper house and a former foreign minister. One grandson of the deceased prime minister is running for reelection to the lower house and a second grandson is up for election for the first time.

Shintaro Abe, Japan's current foreign minister, did his career a favor in 1951 by marrying the daughter of politician Nobusuke Kishi. Abe became Kishi's private secretary; Kishi became prime minister. It was not Kishi's only brush with all-in-the-family politics -- he was the elder brother of a later prime minister, Eisaku Sato.

Just about every postwar prime minister, in fact, has launched the political career of a son or son-in-law. Sato's son has served in the lower house. So has Kakuei Tanaka's son-in-law. Zenko Suzuki's son-in-law -- who is a grandson of yet another postwar prime minister, Shigeru Yoshida -- is running for the lower house.

The process is not always smooth. In Kumamoto prefecture, two candidates are presenting themselves to voters as the political heir to the late foreign minister Sunao Sonoda. The contenders are his third wife and his son from a previous marriage, who are running against each other in the district.

Dynasties are so common that candidates encounter little of the snickering that is so often heard when family members of famous U.S. politicians take up politics. On the contrary, someone running in a father's place may be considered loyal, devoted and probably well connected.

Hiroichi Fukuda, a stout, bouncy man of 72, never lets voters forget his family ties. His older brother, the former prime minister, came from Tokyo to kick off the campaign and appears in color pictures on campaign handouts seated smiling with Hiroichi.

At a brief curbside rally in Ooizumi city this week, the younger Fukuda's warm-up speaker praised the elder brother as "a most senior man in the political world." He went on: "I don't like to make comparisons to professional wrestling, but these brothers are like a two-man team in the ring." The message: together they will deliver for Gumma.

Hiroichi has already served one six-year term in the upper house. Asked what his brother has meant to his career, he replied without hesitation: "He is my heartfelt supporter. He has been my teacher on everything in life. In the election, he is the great central pillar on which I heavily depend."

Hirofumi Nakasone, 40 and bearing some of the youthful good looks of his father, takes a somewhat lower-key approach. He points out the experience he gained as private secretary to the prime minister. "My name has already been well circulated," he told a reporter last week. "If it wasn't, I would have had to start from zero."

Under the Japanese system, the Gumma prefecture will elect two candidates to the upper house. Fukuda is considered likely to win. The second will be either Nakasone or a Socialist contender. In theory, Fukuda and Nakasone are allies, as they are both members of the ruling Liberal Democratic Party. But many people feel the Fukuda camp would prefer a Socialist victory.

That is because the race is widely viewed as a continuation of a 30-year rivalry for national power between Fukuda, the former prime minister, and Nakasone, the current prime minister, both of whom made their careers in Gumma and now represent it in the lower house. A Nakasone loss to the Socialist would be a big loss of prestige for the senior politician.

Many analysts see bloodlines in politics as a holdover from feudal times, when retainers swore loyalty to a lord and his descendants. "It is easier, sentimentally, for us to support a person who has the same name, some blood relationship," said Koji Toyama, spokesman for Fukuda's campaign.

The retainers in this case are members of the politician's koenkai, or support group. Candidates spend years building these organizations. Members pledge their votes, their support and sometimes a percentage of their salaries. In return, the politician provides patronage jobs, help with the bureaucracy and sponsorship of ceremonies such as weddings.

A good koenkai is viewed as something to be passed down through the generations, as a house or family business would be. "A man spends 10, 20, 30 years cultivating his koenkai," said Katsumi Kobayashi, a senior Nakasone campaign official. "When he knows it's time to quit, he feels sorry if all he's built will be given to some unknown, some non-blood person."

Koenkai members, in particular senior ones, are often anxious that the support group remains in the family because that will guarantee a smooth transition and the status in the community that the group accords them.