Board Thread:Questions and Answers/@comment-26359879-20160316031113/@comment-28053036-20160316035941

My rough guidelines for map level and sword type :
 * Lv.1 to 20-ish all swords - Era 1 and 2 (make sure to get them equipped with troops)
 * Lv.20-ish all swords - Era 3
 * Lv.35-ish all swords - Era 4 (4-4 will be harder for tantou/waki)
 * Lv.50 to 65-ish swords (except tantou and waki) - Map 5-1, 5-2
 * Lv.70+ swords (except tantou and waki, and some R2 uchi) - Map 5-3, 5-4


 * Lv.40-ish tantou / Lv.50-ish waki - Era 6-1
 * Lv.60-ish tantou / Lv.70-ish waki - Era 6-2
 * Lv.60+ tantou, waki / Lv.70+ uchi - Era 6-3
 * Lv.70+ waki / Lv.80+ uchi, some tachi and oodachi - Era 6-4

These guidelines isn't a fixed rule as it would be different if you have higher leveled oodachi or naginata that can help babysit your low level swords.

You can check Experience for comparison on experience gained in maps. But generally it is like you said, you get more exp on higher level maps (except some Era 6 maps).