Sayaka's Diary 1 is a file in Fatal Frame IV: Mask of the Lunar Eclipse.
Transcript[]
I saw Ruka standing outside in the garden, bathing in the moonlight.
I rushed out and held her in my arms, but she didn't even seem to notice me, just muttering to herself, her expression completely blank.
As if this weren't enough, she's started to show a fear of mirrors. I have to talk with Dr. Haibara before she buds.
If I don't get her seen to as soon as possible, it may be too late to save her.
There's something I wanted to give to Ruka, but I don't think she's fit to receive it yet.
I'll wait until she gets better and can show me her beautiful smile again...