I didn't understand the idea of friendship when I was a young girl. Perhaps it was the regimented nature of my lifestyle, where everything and everyone had a place in the vertical order of things. One would take orders from someone and then give orders to someone else.

As the iemoto's child, I would have ranked quite highly on the hierarchy. I was used to training with the older students of the Nishizumi school, the ones that had dedicated themselves to learning from my mother in an apprentice-like fashion. I had no issues giving orders to girls who were several years older than I was, and - until I went to school - had little experience with others my age.

Not that school changed me that much. I still felt much more comfortable at home, with the machines that I had grown to know individually, like children. I threw myself into my studies, trying my best not to shame my mother, but with the exception of sensha-do practice, I would head straight home right after the dismissal bell rang. And during practice itself, I would still be commanding, having been picked over the older girls in my third year of school.

In other words, I had no friends.

To be very honest it did not bother me very much at the time. I didn't care to make the distinction between friend and subordinate - as long as they did what I asked them to do and I could see them working hard, I liked them. To me, my crew were my friends, since they were faithful, didn't ask unnecessary questions, and followed instructions to the best of their ability.

But when practice concluded, they would congregate in groups and leave the school together, chattering like birds in the little cliques of theirs - the Panzer IV crew here, a couple of Panzer IIs there, as well the Hetzer girls. It never really occurred to me that I wasn't part of any group - in fact, I can't remember a time when I didn't walk home alone.

I didn't realise it at the time, but my army and I had never spoken as equals. I was not unreasonable to them, and I tried to be as fair and civil to them as possible - but at the end of the day I was the one giving them orders and they were the ones expected to carry them out. I was the source of discipline and victory, but not someone to confide in. I was not their friend.

Now I know that it was probably this very quality that made us such a formidable force. As I had learnt from the very beginning of my training - in the first book I had read on my own from cover to cover - "a great leader does not have undue love for the people". In order to command them effectively I needed the distance. And I didn't really understand that at the time, but I did it anyway.

Now, of course, I have my husband and a handful of close friends. I cannot imagine what it was like for a twelve-year-old to be entirely alone, although I suppose I never was. I had the other disciples, as well as my parents, and I do not recall feeling lonely in my predicament.

Of course, Chiyo changed that.

The more I learned about her, the more I wanted to meet her again. At first I told myself that it was simply a desire for a rematch, but as time passed I couldn't lie to myself anymore. The truth was simple: I wished for a second meeting with her, on or off the battlefield.

It was not long before I got my wish, at the under-16 finals of the 1975 Winter Continuous Tracked Cup. Again we were fighting for the championships, but this time I had the benefit of being armed with six months of drilling and research, for the sole purpose of cutting her down.

It was a close fight, but we won this time. I was careful not to allow her posturing and feinting to shake me, and focused on driving my tanks forward, gradually pushing deeper and deeper like a burrowing knife seeking beating flesh. Focus on yourself. Don't let anyone else dictate what you do. It took every ounce of our willpower to stay in formation and ignore the dancing of the enemy, but we eventually whittled her down to a couple of tanks, while losing three in return. It was a simple matter to kill the remaining escort tank, outnumbered and demoralised, and then we continued to grind forward towards Chiyo, wary of any tricks she would pull. We only let down our guard once the white flag had shot out from her tank.

Water wears down stone. But if the stone is hot enough, the water simply boils away into nothing.

The look on her face when we shook hands after the match was a cross between disbelief and anger. However, after we were dismissed, and I was walking to my mother, she ran up to me again.

"How did you do that?" she asked, and I could tell that she wasn't being sore about it - she genuinely wanted to know what I did that gave me the edge over her.

So I told her. Not everything, of course - and I made sure to rub it in a little, seeing it as fair repayment for the smugness she had displayed half a year earlier - but she took it in stride, absorbing whatever information she could and asking questions of her own. I would have spoken with her for longer, and probably told her more than I should have, if my mother hadn't come to me and separated the two of us with icy politeness.

Just before we went our separate ways, though, she pressed a piece of paper into my hand. Thinking little of it at the time I stuffed it into my pocket as fast as I could, fearing my mother would ask me what it was and perhaps take it from me. I forgot about it and only remembered later that day, when I was going through the pockets of my uniform just before putting it in the washer. It was crumpled from sitting at the bottom of my skirt pocket, and as I unfurled it I saw that eight numbers had been scribbled on it hastily, as well as a messy scrawl that I could just make out as "Chiyo."

Well, well, well, I thought. I dialled the number into the telephone the next day when my mother was at work. The excitement in her voice when she picked up could not be masked, even through the grainy filter of static.

We corresponded infrequently but regularly after that, exchanging thoughts over the telephone when our mothers were out at work. My father never had the heart to stop me - for him, it was the first time I had someone who would speak to me as a friend and he would have never taken that from me, regardless of who it was. We spoke about many topics, but most of our conversations started and ended at sensha-do - tactics, organisation and training. I cannot say that we were companions in the traditional sense of girls our age, that congregated in their cliques every day and gossiped about everything under the sun, but with Chiyo I felt a connection, an actual bond - and I came away from every chat feeling stimulated and refreshed, and looking forward to speaking with her again. It was not ideal that we were only able to see each others' faces during battles, because of the situation between our two families, but I think just hearing her voice was enough to reassure me that I wasn't alone.

And thus it was, through words spoken into a machine and translated into whispers of code, that I found the first friend that would accompany me through the rest of my life.