On 7 August, the source wrote (citation):

On August 16, 2018 (press release of the trade statistics (July 2018 (Provisional)), the base year of Trade Indexes will be revised from Year 2010 to Year 2015. Revision of the base year has been conducted every five years. [...] In connection with the revision, previous data of Trade Indexes will be updated based on the new base year.

In response, we:

1. Archived the predecessors (2010=100, August 2012 to June 2018) by renaming with an "_10" specifier, marking metadata as discontinued, and segregating in the catalog.
2. Created one-for-one replacements (2015=100).
3. Assigned standardized mnemonics.

Dataset properties:

• Measurement: Value and volume ("quantum") indexes relative to 2015
• Adjustment: NSA
• Native frequency: Monthly
• Start date: August 2017
• Source: Trade Statistics Section, Customs and Tariff Bureau, Ministry of Finance

The active series reside in the historical catalog (Japan » Trade » Foreign trade » Trade index by region » 2015=100) and the predecessors under the associated "discontinued" node. They include, for example:

• TRIVOEX_10UM.IJPN   = [DISCONTINUED] Merchandise exports [quantum] - World, (Vol. Index 2010=100, NSA)
• TRIVAIMUS_10UM.IJPN = [DISCONTINUED] Merchandise imports [value] - U.S., (Index 2010=100, NSA)
• TRJEXUM.IJPN        = Merchandise exports [quantum] - World, (Vol. Index 2015=100, NSA)
• TRIIMIASIAUM.IJPN   = Merchandise imports [value] - Asia, (Index 2015=100, NSA)

About the dataset

The source reports an overall index ("world") and in this table breaks out four major areas: U.S., EU, Asia including China, and China. A separate table summarizes 36 countries and 10 regions. Other tables break out commodities traded with ASEAN, Middle East, Russia, and South Korea. The tables are not numbered.

In direct communication with the source, we have clarified that the EU aggregate is "changing composition", that is, it includes trade with the members of the EU at any particular time, from nine in 1979 to 28 in 2013.

The term "quantum" for the volume index is also used by Hong Kong.

References

• Indexes of trade - Data by major regions
• Revision policy (corrigendum)
• Press releases
• News items
• Code lists based on HS
• Glossary

See also

• Data Change: Japan - Trade Index - Rebased to 2010 (Aug 2013)
• Data Change: Luxembourg - Trade Indexes - Rebased (Jun 2013)
• Data Revision: Hong Kong - Merchandise trade index - Re-referenced to 2016 (Mar 2018)
• Trade price indexes rebased
• Other recent operations re: Japan
• Using Data Buffet: EU geo codes and geo lists

Updates

• 29 Aug - Initial version
• 4 Sep - EU changing composition