I've shown cards from Sports Graphic Number in the past - the most recent issue being a set for Tomonori Maeda, the recently retired Carp legend. When SGN isn't busy publishing their magazine, they put out player-specific sets of currently ultra-popular stars.
BBM also releases player sets, but while BBM has smaller box sets, SGN goes with pack-based sets. SGN cards also have very little text, instead just showing dozens of images of the player.
SGN has issued a few non-baseball sets too but I've yet to buy one.
Each box contains ten packs of seven cards each - six regular cards plus one Special card. There are also rare cards:
- Relic cards with visitor uniform, home uniform, or undershirt, plus patch cards
- Three different styles of signed cards, including "signed ball" cards
- What appears to be foil-signed rare cards
- What appears to be "photo" cards
Additionally, special promotional/reservation cards were issued.
Each box doesn't necessarily include a hit above, though I would think the intent would be to include one. With 70 cards in the box, the 5000 yen price tag is pretty high per card if you only get regular and insert cards.
With perfect collation, it's possible to complete the base set in two boxes, the Special cards in two boxes, and the Box Privilege cards in four boxes.
Some details for this post came from Japanese Baseball Cards. All images are from my collection.