Incorrect Data

I'll take this up when I get home. I have a giant with no shield mastery. I'll rank up shield mastery and record results for each rank with various shields. For the sake of completeness, I will be checking each rank with a Cooking Table, a Spell Book, a Holy Eagle Mask, a Guard Cylinder, a Round Shield, a Kite Shield, and a Vales Shield.

Sounds like a plan! Thanks!

Didn't have time for this last night because I got home later than I usually go to bed. I'll try again tonight.

Here's the new data.

I had to switch out the kite shield for a tikka shield since I was using a giant. I also didn't have a small shield that wind guard identified as a shield since the round shield was human/elf only. If someone trains shield mastery in the future on a human, please check if the data matches up with the first 4 on that table.

Round Shield with Rank 1 Mastery gives me the same values as a Rebis Guard and a Cooking Pot.

However I'm oddly getting 8 more magic defense from all three, as what the JP data says.

A few things:

1. The numbers for magic protection are off by one because Blargel's giant had too low intelligence (-1 is displayed as 0).
2. We suspect the protection, magic defense, and magic protection use fractions, resulting in variance here. I'll confirm this over the weekend.
3. The fact that defense at rank 1 for a medium shield is 21 is unexpected. We need to research why this is.

About the fractions thing, I confirmed this with the following steps:

1. Have 154 will, which translates to 14.4 magic defense. This will display as 14 on the char screen.
2. Equip a cooking table. The char screen displayed 21 magic defense, showing a 7 magic defense increase.
3. Level up until my will to 155, which translates to 14.5 magic defense.
4. Observe the total magic defense increase to 22.

This seems to imply that at 14.4 base magic defense , 7.5 magic defense was being added, resulting in 21.9, but displaying rounded down was 21. Increasing my base magic defense to 14.5 caused my total to go to 22.0.

So here's what we have:

1. Large shields grant a certain amount of defense, protection, magic defense, and magic protection for each rank.
2. Medium shields grant 70% of this.
3. Everything else grants 50%.
4. Fractions are combined with fractions from other sources (e.g. will) and rounded down in the display.
5. Defense is treated like an enchant, thus always rounding down.

Are three tables needed with this? Aside from Rank 1, "70%" and "50%" seem good enough.

Good find. I do believe we should keep the three tables for ease of reading. We don't want the wiki users doing math they don't have to do in order to figure out what their bonuses are or will be. We could add in the extra decimal values to be more accurate though and add a footnote similar to your 4th point.