1. 1 Latest Progress of the BOJ’s XBRL Project Outline and Some Empirical Feedback December, 2007 Yoshiaki Wada Financial Systems and Bank Examination Department Bank of Japan © 2007 Bank of Japan 16th XBRL International Conference in Vancouver

2. 2 1. Introduction of the BOJ Tokyo Maebashi Fukushima Sendai Aomori Kushiro Sapporo Hakodate Akita Niigata Matsumoto Kanazawa Okayama Kobe Matsue Hiroshima Shimonoseki Kitakyushu Fukuoka Nagasaki Kumamoto Kagoshima Oita Matsuyama Kochi Takamatsu Osaka Kyoto Nagoya Shizuoka Kofu Yokohama Naha  Central Bank of Japan, established in 1882  32 branches nationwide © 2007 Bank of Japan Head Office in Tokyo

3. 3 © 2007 Bank of Japan 2 ． Monitoring Coverage of Financial Service Institutions Major Banks Regional Banks Shinkin Banks Foreign Banks Securities Firms, etc. Bank of Japan Importance of efficient data gathering scheme Monitoring data from about 570 FSIs BOJ covers about 570 FSIs and gathers various daily, weekly, monthly and annual data for monitoring.

4. 4 © 2007 Bank of Japan 20032004200520062007 Preparation for testing Tool and taxonomy development Live Use ･ Release of the Monthly B/S Taxonomy on banking a/c ･ Revision of the Monthly B/S Taxonomy ･ Release of the Taxonomy Setting Tool ･ Release of the Monthly B/S Taxonomy on trust a/c ･ Release of the Monthly Lending Rate Report Taxonomy 3 ． Project history Three-phase test

5. 5 © 2007 Bank of Japan 4 ． The BOJ’s XBRL based reporting scheme ② D/L of necessary taxonomy set ⑤ D/L of ＸＢＲＬ data ① U/L of taxonomy set to the library FSIs ＸＢＲＬ③ data creation and validation Data creation tool Error-free data files BOJ Error-free data files IP-VPN Database Post data validation Taxonomy library Taxonomy setting tool Taxo2 Ta xo3 Taxo1Taxo2 Earlier data release for users ④ U/L of XBRL data Select the taxonomy according to the report type Develop the taxonomy set according to the report type Excel XBRL Check for errors using the function of Formula-Link and correct the file XBRL

6. 6 © 2007 Bank of Japan 5 ． Features of the BOJ’s XBRL reporting scheme (1) 1 ． All necessary tools, taxonomy, and data communication infrastructure are supplied by the BOJ for free. ⇒ After receiving the necessary taxonomy set, FSIs can promptly generate XBRL data and report it to the BOJ. 2 ． FSIs can generate the XBRL instance file, without any third-party assistance. ⇒ Data security is improved. 3 ． By using Formula-Link, data accuracy is improved. ⇒ Cost of data handling can be minimized both for FSIs and the BOJ.

7. 7 © 2007 Bank of Japan 6 ． Review of the last 20 months of live use (1) ⇒ Our XBRL tool has worked without fatal problems. 1. No down time ⇒ The reliability of the tool and availability of the total reporting workflow were confirmed. 2 ． All FSIs submitted monthly B/S data in XBRL format ⇒ Although XBRL was not mandatory in our reporting scheme, all FSIs submitted data in XBRL format voluntarily. ⇒ FSI’s degree of recognition of the new reporting scheme increased steadily.

8. 8 © 2007 Bank of Japan 7 ． Review of the last 20 months of live use (2) 3 ． Revision and re-distribution of the current taxonomy and the release of the new range of taxonomy ⇒ The taxonomies have been revised several times due to revisions to Japanese company law or the requirement for new data. ⇒ A new range of taxonomies, such as those for monthly B/S of trust accounts and lending rate reports, was released. 4 ． Enhancement of efficiency of FSIs’ reporting work and the BOJ’s data processing ⇒ Decrease in manpower required for data reporting in the FSIs and for database operation in the BOJ ⇒ Earlier release of the accurate data to the BOJ’s data users.

9. 9 © 2007 Bank of Japan 8 ． Increased efficiency in the data reporting scheme (1) No more post data correction via telephone Excel Template for data input XBRL Taxonomy –set A Taxonomy setting tool Data conversion tool (X-Port) Formula-Link Error check Error correction From BOJ To BOJ Error- free XBRL Taxonomy –set B Taxonomy –set C

10. 10 © 2007 Bank of Japan Changes of the BOJ’s business flow on the Monthly B/S data processing Report deadline day XX+1 X+2~4 X+5X+6 day XX+1 X+5X+6 Preparation of data U/L Data U/L and validation within DB Data processing within DB Data release for BOJ users Error correction Data validation by XBRL, prior to data submission Reduction of post validation cost Reduction of post validation cost Data validation by XBRL, prior to data submission Reduction of post-validation cost Old Flow Early data release （ 2 to 4 days) Short cut! New Flow 8 ． Increased efficiency in the data reporting scheme (2)

11. 11 © 2007 Bank of Japan Reduction of the required part-time manpower in the BOJ’s database team 8 ． Increased efficiency in the data reporting scheme (3) XBRL went live (Feb. 2006) Dotted line : Before XBRL Solid line : After XBRL

12. © 2007 Bank of Japan Three key factors for the better performance taxonomy; 9 ． Some empirical feedback from BOJ’s XBRL Lab.(1) Proper taxonomy size Proper combination of Formula-Link and Dimensions Prototyping and performance tuning with bench mark test 12

13. © 2007 Bank of Japan Proper taxonomy size: 9 ． Some empirical feedback from BOJ’s XBRL Lab.(2) Within the BOJ’s reporting business model, there is a rule which limits every taxonomy volume to a certain size, for the following reasons:  Stress-free data transformation and validation using X-Port within the limited capacity of FSIs’ PC  Smooth delivery of taxonomy to the FSIs under the limited capacity of IP-VPN ⇒ Currently, the zipped file size of each taxonomy set is limited to 2 MB 13

14. © 2007 Bank of Japan Importance of proper combination of Formula- Link and Dimension-Link ; 9 ． Some empirical feedback from BOJ’s XBRL Lab.(3) Merits Flexibility of taxonomy design Reduction of items, Presentation –Link and Definition-Link Easier setting of concepts Demerits Complicated Formula-Link setting, caused by the unavailability of relative context ID for the item Increased process time for data reading and analyzing for Formula-Link Merits & Demerits of Dimensions 14

15. 6 items Deposit 1 2 3 4 5 6 Hypercube1 Dimension1 Ⅰ Ⅱ Ⅲ Dimension2 A B C : Q ＊＊ © 2007 Bank of Japan An example of Dimensions use case (1) Original Reporting FormFlat TaxonomyTaxonomy with full Dimensions 9 ． Some empirical feedback from BOJ’s XBRL Lab.(4) Increase of Complexity ＊ ＊ ＊ ＊ ＊ ＊ Instant & Duration Deposit Table Ⅰ Ⅰ 1A Ⅰ 2A Ⅰ 3A ： Ⅰ 6Q Table Ⅱ Ⅱ 1A Ⅱ 2A Ⅱ 3A ： Ⅱ 6Q Table Ⅲ Ⅲ 1A Ⅲ 2A Ⅲ 3A ： Ⅲ 5C Others 102 items 312 concepts 2 context 102 items 6 items Sum of ＊ 32 items 102 context 32 facts 17 items 17×3×2 6+17+sum of ( ＊ & ＊＊ ) 15

16. © 2007 Bank of Japan An example of Dimensions use case (2) Observed Result of Taxonomy Bench-Mark Test 9 ． Some empirical feedback from BOJ’s XBRL Lab.(5) (a) Number of Concepts (b) Number of Member Item other than Concepts (c) Number of Contexts (a)×(c) Number of Facts (a+b)×(c) Number of Possible Facts Time for Data Read to X-Port Tome for Data Validation by Formula- Link Case1* Flat taxo3066261262423 sec3 sec Case2* Taxo with full DM 626102612326433 sec15 sec Case3* Taxo with partial DM 5191261272022 sec3 sec Test Condition; Tool : BOJ X-Port CPU : Pentium M 2GHz, with 2GB memory * Case1 to 3 were build on the same reporting format. The only difference is the use of dimensions. + 20 items 16

17. © 2007 Bank of Japan 9 ． Some empirical feedback from BOJ’s XBRL Lab.(6) Number of Items affects processing time Increased dimension’s member items affect processing time!! 6 ｃｏｎｃ ｅｐｔ s Deposit 1 2 3 4 5 6 Hypercube1 Dimension1 Ⅰ Ⅱ Ⅲ Dimension2 A B C : Q ＊＊ ＊ ＊ ＊ ＊ ＊ ＊ Number of Member Items Other Than Concepts Flat Taxo Case : 6 (=sum of ＊ ) → Taxo with full Dimensions: 26 (=sum of ＊ & ＊＊＆ 17 ） Original Reporting FormTaxonomy with full Dimensions 17 items 17

18. © 2007 Bank of Japan How to make an efficient Taxonomy? 9 ． Some empirical feedback from BOJ’s XBRL Lab.(7) Complexity of Taxonomy (i.e. Number of Possible Facts) Work-load of building taxonomy Data processing time Optimal point ! 18

19. © 2007 Bank of Japan How to find the optimal point? Important 3 steps 9 ． Some empirical feedback from BOJ’s XBRL Lab.(8) 1st. Measure the Number of Possible Facts of the flat taxonomy case = Basic Index 2nd. Design the structure of taxonomy with Dimensions so that the Number of Possible Facts can be small as the Basic Index level 3rd. Make a prototype, measure its performance by bench- mark test, and tune the structure Some new treatment should be done in the Spec Level? 19

20. © 2007 Bank of Japan 10 ． Next steps (1) Advancement in taxonomy design Version-up of current XBRL data conversion tool Design of new XBRL database ⇒ New version of taxonomy with Formula-Link and Dimensions ⇒ Establish the more sophisticated tuning method ⇒ Adaptation to Windows Vista and enhancement of processing power in the core engine of the tool 20

21. 21 © 2007 Bank of Japan Design of XBRL Database Issues to be solved How to manage the relation of XBRL instance and taxonomy How to generate consistent time-series data from different instances and taxonomies How to utilize the XBRL meta-data for efficient data analysis How to reduce the cost of database operations 9 ． Next steps (2)

22. 22 © 2007 Bank of Japan For further information, contact yoshiaki.wada@boj.or.jp

23. 23 © 2007 Bank of Japan Thank you for your attention.