I meant pictures of the entire instrument. You know, as is tradition here on the Basses subforum.
Back to discussing strings, they do look larger than the Rotosounds.
If roundwounds are fine by you, check out the Dogal Tiny Boy RW160TB. They're also 45-105, but they probably have round-section, thin cores and should be noticeably more flexible, and perhaps also have less tension proper (lengthwise pull).
If you're open to exploring flats, Dogal also makes a flatwound version, the JC106TB.
Both the above options shouldn't be too hard to find in Japan. Here they are, for visual reference, on the Tiny Boy website:
Category: Strings
Alternatively, this nylon-core, nickel-wound flatwound set that Pyramid makes
Tiny Boy Basses
has been reported to work on a Tiny Boy 23" electric bass (there is enough metal on the string to be 'read' by magnetic pickups):
Tiny Boy Basses
^ [If interested, read the following post till the end - the secret is turning up the gain control on the amp.]