I was caught at another traffic light. I pulled on the handbrake and turned to get a proper look. A small box had fallen under the seat. Mr Yanagi must have dropped it. If he’d dropped the ring he was due to offer his girlfriend, what was he doing now without it? I wondered. I was worried, but cannot deny I was also a little grateful to Mr Yanagi. Yuni had been a little tense ever since she had first spotted me, but now, thanks to the ring, she seemed happy and relaxed. I reached down, retrieved the box and placed it on the dashboard. The dark red ribbon was reflected in the windscreen like a flower.

Yuni’s house was close by.

‘I’m back!’ she called as we entered. ‘And I brought the tuner with me!’

Kazune appeared from the back room. ‘Great! I thought I wasn’t going to be able to play the piano today. It was agony! I was beginning to wonder how I was going to sleep tonight.’

‘Right,’ I said, although ‘agony’ felt a little disproportionate here.

I stepped across the carpet to the piano and opened up the lid. Testing the keys from one end to the other, one very noticeably became stuck.

‘Ah, here’s your problem,’ I said, my nose inches away from the strings inside.

‘Can you fix it? You can fix it, can’t you?’ said the twins in unison, a little desperately.

I was happy to reassure them.

The flange that connected the hammer and the key had seized up. A slight adjustment and it would be back to normal.

‘At this time of year you have to be careful of the humidity,’ I commented.

Pianos are precise instruments made of wood. All piano tuners have it drummed into their heads to notice humidity levels, particularly in autumn and winter. If the humidity level gets too high, the wood expands. Screws loosen. Steel rusts. The tone will slip. Things are different here in Hokkaido. Humidity will still alter the sound of a piano, but what we have to be more careful of in autumn and winter is dryness. Low humidity, in other words.

‘Thank you so much,’ the twins said.

I pressed the key to test it, and the hammer lifted naturally. It was a simple fix.

‘Could we try playing it?’ Yuni asked.

‘Of course.’

Yuni took her place in front of the piano. Kazune sat beside her on the other stool. Within moments they had launched into a duet.