**Chinese book sizes**

In China they have a special system for book printing, which is based on dividing up an uncut sheet of paper that measures 88cm x 123cm. So dividing up the paper into 16 is called “16开” or “16开本”. So for example if you divided the paper in four, the paper size for your publication would be called 4 kai (四开). This system is complicated by the fact there is no official, universal paper size, so if someone says 8 kai or 16 kai it’s a rough guide – you must confirm with your printer the specifics. However, as a rule of thumb you can check on the following to get a rough idea of the equivalent international paper size:

Chinese term | Approximate international paper size equivalent |

全张（不分）
正度787 x 1092mm 大度 889 x 1194mm |
A0
841 x 1189mm |

对开本（2张）
正度546 x 787mm 大度 597 x 889mm |
A1
594 × 841mm |

四开本（4张） 4 kai
正度389 x 546mm 大度 444 x 597mm |
A2
420 x 594mm |

六开本 6 kai
正度370 x 520mm 大度 285 x 420mm |
A3
297 x 420mm |

八开本 8 kai
正度260 x 370mm 270 x 390mm 大度 258 x 420mm 295 x 440mm 大8开本 262 x 374mm 小8开本 260 x 368mm |
A3
297 x 420mm |

十六开本 16 kai
正度185 x 260mm 大度 210 x 285mm 大16开本 187 x 262mm 小16开本 184 x 260mm |
A4
210 x 297mm |

三十二开本 32 kai
正度185 x 130mm 大度 142 x 210mm 大32开本 140 x 203mm 小32开本 130 x 184mm |
A5
148 x 210mm |

64开本 64 kai
大64开本 101 x 131mm 99 x 130mm 小64开本 95 x 127mm 92 x 125 mm |
A6
105 x 148mm |

Image by Bromskloss

Note that where I am (China) there is a limit on large volume printing sizes: The widest they can do is 70cm (there’s no limit on length, it’s a roll of paper). So for the largest available print size, a handy size would be:

Posters: 70cm x 99cm

This is at the A series aspect ratio, roughly 1.41:1. There’s a good calculator here. Posters are often 50cm × 70cm, almost a B2 size.

On some nice postcards bought online (the easiest way in China), I read the mention “787 x 1092 mm 1/32”. Since “787 x 1092mm” is the 正度全张 (full paper size), “1/32” means 三十二开本 (a 32-fold), so the size of my postcards is 185 x 130mm (as per your conversion table). This is not obvious. Initially I was figuring that 32张 should be 787/4 x 1092/8 = 197 x 136 mm. In fact, not. Thank you for these explanations and the conversion table.