Her family didn't realise what had happened. "They were under the impression that I was playing with myself."
It continued for two years. "I do remember that it only happened during the daytime. I assume that he was babysitting."
Two older boys and her next-door neighbour sexually abused her, too. "I used to go over there to play his piano. Although I knew he'd do things, I still went.
"I blamed myself. I thought I was a hugely naughty girl and I was too afraid to tell anyone."
When Shona (not her real name) was 6, her grandfather died, and the abuse ended. But her self-image was fixed. She got into "alcohol, drugs, sex at a young age, all that."
"I was too afraid to say no. I was easily abused and I continued up to my 30s to be hurt."
Finally, she stopped drinking. At 37, she now looks after her three children by herself.
She credits five years of counselling - both group therapy, where it was "just amazing to know that I was normal, as far as survivors were concerned", and weekly one-to-one sessions which attract a $50 subsidy each time from the Accident Compensation Corporation (ACC).
ACC also pays for three hours' childcare for each session.
"I seem to be very lucky because the ACC has been wonderfully helpful to me. My case managers have been wonderful and that takes the pressure off."
There are thousands of women like Shona. Not all have found help.
Yet there is another side to this issue. In 1992 Gordon Waugh, of Whenuapai, was accused by his daughter of sexually abusing her 30 years earlier.
On the website of the organisation he co-founded, Casualties of Sexual Allegations (Cosa), Waugh writes: "I had committed incest with her. I had fondled her breasts. When she was a baby ... an uncle had taken her on a trip from Auckland to Whangarei and had inserted his fingers into her vagina. The fact that we lived in Blenheim at the time, not Auckland, escaped her."
There were "many, many other allegations", but Waugh says none of them checked against the facts.
His daughter, supported by her sister, complained to the police that Waugh had indecently assaulted her. Police investigated but no charges were laid.
For Waugh and his wife Colleen, it was "like a death in the family". They haven't seen their daughters for 10 years, and have no contact with four grandchildren and a 1-year-old great-grandchild.
Waugh blames the ACC. Not only did it pay the counsellor who helped his daughter to "recover" her memory, but it also paid his daughter lump-sum compensation of up to $10,000.
Ever since, Waugh has fought the issue. He laid a criminal complaint against the counsellor to the police, which was not acted on. He has spent a decade pursuing the ACC, the Ombudsman and the Privacy Commissioner to obtain the details of what his daughter received.
"A few days ago, I received the Privacy Commissioner's final opinion," he told the Weekend Herald a week ago. "I believe he has been captured by the nonsense spoken by counsellors generally."
Waugh, too, is not alone. A Porirua man tells how in 1989 a lesbian couple asked him to donate sperm so they could have a baby. He was surprised but said, with a smile, "I suppose I could make the ultimate sacrifice." Then he went on holiday, and came back to find his house plastered with the word "Rapist!"
He called the police, who suspected that it was done so that the couple could get a $10,000 lump sum from the ACC to compensate for his "abuse". The police officer who came round said, "This is happening all over the country."
At the peak, in 1992, 6000 people lodged sexual abuse claims with ACC in just three months, up dramatically from 2173 in the whole previous year and 1075 the year before that.
In the same year, Christchurch Civic Creche worker Peter Ellis was arrested on charges of sexual assault. There were similar cases in the United States and Australia.
Partly in response to the surge of sexual abuse claims, the National Government abolished lump-sum compensation for all accidents from October 1992.
Sexual abuse claims to ACC dropped almost as quickly as they had risen, from 10,892 in 1992-93 to 4872 in 1999-2000, before rising slightly to 5580 in the year to last June.
In October 2000, Waugh wound up the Auckland branch of Cosa after "a lengthy period without any new cases" of false sexual abuse allegations. The organisation continues only in Christchurch.
But he worries that this may be about to change. Ten years after lump sum compensation was abolished, Helen Clark's Labour Government is restoring it from April 1.
Last month Christchurch law firm Wakefield Associates sent fliers to 1 million households telling sexual abuse survivors: "You may be entitled to a lump sum of up to $25,000 and ongoing payments valued in excess of $150,000."
Waugh is also concerned that the ideology of "recovered memory" still flourishes - especially in the clinical psychology doctoral programme at Auckland University, the country's largest source of trained psychologists.
A friend and former lecturer at the university, Dr Robert Mann, says students have been refused admission to the doctoral programme if they did not affirm belief in recovered memory.
The senior professor in the psychology department, Professor Mike Corballis, says that when he was department head a few years ago he was worried about the way students were chosen for the programme on the basis of their "suitability" to be psychologists, rather than their academic records.
"There were rumours that you had to cry," he says.
Corballis set up a committee including outside psychologists to make the selections. But Waugh and Mann continue to be suspicious, partly because the course's co-director, Dr John Read, is an outspoken survivor of sexual abuse and has devoted much of his career to researching the effects of abuse on people's later mental history.
As Corballis puts it: "He is often very emotional in giving talks about sexual abuse. He certainly has an emotional impact on the students."
Trying to sort the facts from the emotion in such a highly-charged field is difficult. But, as Shona's life story shows, there is no doubt that sexual abuse can have traumatic long-term effects.
An Otago University survey of 2000 Dunedin women in the late 80s found that 32 per cent said they had been sexually abused before the age of 16. Of these, 20 per cent had experienced genital contact, and 6 per cent actual or attempted intercourse.
The perpetrator was a family member in 38 per cent of cases, an acquaintance for 46 per cent and a stranger for 15 per cent. One in 10 stepfathers and one in 100 natural fathers had sexually abused their children.
The study found a clear link between childhood sexual abuse and later mental illness.
Even after allowing for other casual factors such as broken families, women who suffered sexual abuse involving intercourse in childhood were 12 times more likely than the average woman to be admitted to hospital for psychiatric care later.
Clearly, some sexual abuse claims are false. But ACC says it gets proportionately fewer false claims for sexual abuse than for other injuries.
Three former students of the clinical psychology course at Auckland University, and a support person who was present at another student's entry interview, all say recovered memory of sexual abuse did not arise in their interviews.
"My feeling is that you have to toe the line with them, yes. You have to basically agree with everything they say or you might have problems," one former student says.
"But it's like teacher training - you go through it and take everything with a grain of salt. I don't think everyone comes out thinking that sexual abuse is the cause of everything."
Another former student says most students in the course also take papers in psychiatry, where there is scepticism about recovered memory. "We are exposed to both sides."
Counsellors say ACC has become much more restrictive about giving financial compensation for sexual abuse since 1997, when it began using American Medical Association guidelines to assess how much people's functioning has been impaired by their injuries.
"Independence allowances", a weekly payment which replaced lump sums in 1992, have dropped from 2.7 per cent of all sexual abuse clients in 1996-97 to just 0.8 per cent in 2000-01.
Although lump sums are being restored this year, the same AMA guidelines will restrict them to a tiny fraction of people who are sexually abused from April 1 onwards, and then only after their condition has stabilised enough to determine whether they are permanently "impaired".
Sensitive claims manager Gail Kettle expects that most of those who do receive lump sums will get only between $2500 and $5000.
At the same time, she is tightening controls on the 700 private sector counsellors who get ACC subsidies for sexual abuse cases. From later this year, a new group of clinical psychologists and psychiatrists will assess all clients independently after 10 counselling sessions.
Ten years after complaints peaked, there are tentative signs that increased public awareness just may be starting to change the actual level of abuse. Sexually abused children admitted to Auckland's Starship children's hospital child abuse units have fallen from more than 700 a year in the early 1990s to 300-400 in the past year.
Criminal convictions for sex offences against under-17-year-olds dropped from 2066 in 1996 to 1173 in 2000.
But former Children's Commissioner Ian Hassall, now at Auckland University of Technology, says it would be too much to expect a big change in behaviour in 10 years.
"In the Otago study, there was no significant difference between older and younger women, so over that period there hasn't been any change in the incidence of sexual abuse," he says.
"It's also a problem that occurs in every society that one knows of."
Shona believes her grandfather's behaviour was a power issue.
"I thought maybe he wasn't getting it from my grandmother. She was quite a tyrant. Did he need to become powerful by using me?" she asks.
Dr Miriam Saphira, a psychologist who worked for 12 years with sex offenders at Mt Eden Prison, says the men abused children because they were "unable to express their emotions" and so had difficulty in adult relationships.
John McCarthy, who runs Auckland's Safe Network programme for child abusers, says many offenders have been sexually abused as children themselves or come from troubled families - problems exacerbated by social influences.
"We live in a society that is pretty sexualised and there are sexual images that come by way of things like pornography and parts of the media."
His programme tries to change the men's attitudes and sexual arousal patterns - "giving the men a sense of control over their thought patterns and their fantasies around children".
"We are developing in the men a sense of real understanding and awareness of what it's like to be a child who experiences sexual abuse at their hands, so it isn't some 'romantic encounter' that occurred but a harmful, aggressive, violent, coerced situation."
McCarthy says his programme works. In a follow-up study on adolescents who went through it, none had reoffended 18 months later.
Hassall believes sexual abuse will stop only when non-offenders stop "turning a blind eye when they think that something like this is going on".
He suggests that communities could declare themselves "child abuse-free" in the same way that many adopted "nuclear-free" status in the 1980s.
To qualify, local businesses would need to cater for children and let their parents take time off work when they needed to care for them. Children would be acknowledged as "part of the world, not hidden away somewhere as a shameful badge of inefficiency".
"We might pay less attention to sponsorship of sport and a little more attention to sponsorship of families with children in need, through groups such as Barnardos and Plunket.
"When you start looking at it constructively about what each person can do, there are a lot of things that every social institution and every part of the social fabric can do."
