I just took a look Dave - and they have index cards too ! .... oh my !
This series comprises some 50,000 pre-printed cards of uncertain provenance. They appear to have been compiled by a central Japanese authority which has not been identified. There has been some degree of Allied assistance in compiling, maintaining etc.
The index cards record (with certain exceptions, consistently) the following details:
Camp (may be subject to change due to transfer) (In Japanese);
Name;
Nationality (In English, or English and Japanese);
Rank (In English, or English and Japanese);
Place of Capture (In English, or English and Japanese);
Father's name;
Place of origin;
Destination of report (assumed to be report of capture, sent to next of kin at address given);
'No' i.e. Prisoner's Camp Number (established by comparison with other records) (May be subject to change due to transfer) (In Japanese);
Date of birth;
Unit and service number;
Date of capture (In English, or English and Japanese);
Mother's name;
Occupation (In English, or English and Japanese);
Remarks;
Other information (on reverse) which may include medical details. (In Japanese, possibly partly translated).
Diagonal red lines across some cards appear to indicate that the prisoners were dead.
Whilst for Prisoner's Camp Number the relevance of a number has been established, the significance of other numbers or letter/number combinations has not been established.
Arrangement
All those cards marked in red along the top right edge are also stamped in the top left corner with a rectangular box marked with four Japanese characters which have been interpreted simply as 'File Reference'. The boxes contain sequential numbers 1-11,838, and it may be that these cards were originally maintained separately.