A series of "bishōjo"-centered manga booklets that were released weekly for a short time in Japan.
The manga would come packaged with a limited edition plastic-figure assembly kit, designed by Ohshima Yuki, of the featured character of the week:
Volume 1 - New! - Figure for volume 1 - Mion
Volume 2 - Two! - Figure for volume 2 - Ashita
Volume 3 - Hot! - Figure for volume 3 - Harusame
Volume 4 - Why!? - Figure for volume 4 - Sonome
Volume 5 - Bye! - Figure for volume 5 - Eruron
Bonus volume - eXtra! - Figure for bonus volume - Tetora
There is a conspicuous absence of the brothers (oniichan) of the title, as only the little girls are 'portrayed.
(Source: MU)

Ichigo Mashimaro follows the life of Nobue Itoh, her younger sister Chika, and her friends. The basic premise of the show can be summed up in "cute girls do cute things in cute ways", be it trying to quit smoking, going outside to play, celebrating a holiday, or doing school work.