What is the JCE?
The JCE is a Japanese website which has lots of information about the first Xenoblade Chronicles game.

Cool, you guys can read Japanese? Can you help me with some other project that's in Japanese?
Unfortunately most of us can't read Japanese. Instead we use Google Translate to read the site in English.

Help! None of the names of things match up to the names of stuff in the game.
Yes, Google Translate is annoying like that. Flanqer has posted translations of some portions of the JCE to pages in his user space.

For pages Flanqer has not translated, you can consult the Translation Notes and Translation Notes 2 pages for help on gems, monsters, materials, arts manuals, weapons, and armour. Please note however that Google Translate's translations change over time, and these pages are not currently maintained.

The website is called "xenobladedata" so why do you guys call it the "JCE"?
On the front page of this wiki, the text for the link to the xenobladedata wesbite is "Japanese Comprehensive Encyclopedia", which we've shortened to JCE.

Where did the JCE get its data?
We don't know. Some users have theories and opinions and might be willing to share them.

How did they get those pictures on the JCE?
See previous answer.

How accurate is the JCE data?
Pretty accurate. Sometimes rates for things don't add up to 100% when they should, and UnnamedBonus (who makes extensive use of the JCE) has found a few errors. These might be due to differences between the Japanese and Western versions of the game.

However, sometimes things do get messed up during translation. Two issues have been identified in this area.

The most prevalent issue is with certain Machina weapons being incorrectly translated. As of July 2014 Google Translate is sometimes rendering Machina Staff IIs and Machina Sniper IIs as Machina Staffs and Machina Snipers instead. This currently does not affect other weapons, and appears to only occur when one of these weapons has 2 gem slots.

Because of this, it is advised when working with any page which references Machina weapons to double-check the translation against the untranslated JCE. Since the Japanese version uses western numbers, it is easy to tell when a number has been dropped.

A second issue has been identified where the translation will rarely list an incorrect drop rate. This issue is also active as of July 2014. In the case identified the translated text indicates a 5% drop rate for an item which the original Japanese indicates as having a 10% drop rate.

Because of this, editors who believe they have found an incorrect drop rate on a page are advised to check the drop rate against the Japanese version of the JCE and not rely purely on the translation.

How complete is the JCE data?
To the best of our knowledge, the monster drop tables and NPC trade lists are complete. For other things, the level of completeness varies. In particular, the JCE doesn't always list all sources for gems, materials, weapons, and armour.