‘Kodaka-san left a file with me. He took it with him to Fukuoka, so it was not there when the office was broken into. I received the impression that he had taken it with him to guard against such an eventuality.’

So much for the forgotten notebook, Wada reflected. This file was what he’d gone back to the office for on Saturday morning. Which meant it was central to the case. ‘What does the file contain?’

There was a delicate pause before Dobachi replied. ‘Numerous documents. I have not inspected them. Kodaka-san did not authorize me to do so. But he did authorize me to pass the file on to you. If you want me to.’

Wada assumed the file was one of the many bulging manila folders Kodaka lodged in his filing cabinet. ‘What is written on the front of the folder?’ she asked. Something always was, in Kodaka’s scrawled hand, though not always something helpful. Kodaka played little shorthand games with himself when it came to record-keeping.

In answer, Dobachi used the word kage-boshi, which meant a shadow, specifically a shadow of a person. And Wada instantly remembered what Kodaka had said to her about Hiroji Nishizaki and his business activities. Some cases I have handled bore his shadow. ‘You know what this means, Wada-san?’ Dobachi asked.

‘I think so, yes.’

‘You can direct me what to do with the file. Kodaka-san was very clear that it would be a matter for you … in his absence.’

A matter for her. Wada might have been angry with Kodaka for putting her in such a position. But anger never came easily to her. Her mother had often complained she was altogether too calm for her own good. Well, that was her nature. Just as obliqueness had been Kodaka’s.

‘If you wish,’ Dobachi continued, ‘I can store the file in my safe here. Or … I can destroy it.’

‘Please do not destroy it.’ Her reaction to the idea was instinctive. She couldn’t bear to think of the material Kodaka had carefully amassed being shredded or incinerated.

‘I will store it, then. Unless …’

‘Can you send it to me?’

‘Of course. Kodaka-san gave me the address of your hotel. But please consider carefully, Wada-san. You are not obliged in any way to pursue this matter. It could be argued that it is not even appropriate for you to pursue it now the Kodaka Detective Agency is no longer functioning. It might be altogether wiser for you to … drop it.’

‘By wiser you mean safer?’

It took Dobachi several seconds to summon an answer. But, when it came, it was unambiguous. ‘Yes.’

Wada thought for a moment, then said, ‘May I call you back later with a decision?’

‘Please do. I will be here most of the day.’

‘Thank you, Dobachi-san.’