At the conclusion of each mission your ninja techniques are reviewed. Your score and rank will depend on how many enemies you killed and under what circumstances. If you score a high rank your ninja items will be increased. Score the highest rank, Grand Master, and you will be rewarded with a special Grand Master item per mission.
A break down of the scoring system and ranking for Tenchu: Wrath of Heaven when playing with Ayame or Rikimaru is given below. Tesshu’s Ranking System can be found here.
| Task | Breakdown | Points | ||
 |
||||
| Undetected Kills | Undetected kills | + 20 | (for each) | |
| Detected kills | Detected kills | + 5 | (for each) | |
| Spotted | Finishing mission | +300 | ||
| Spotted | – 30 | (for each) | ||
| Not spotted bonus | +150 | |||
| Innocents | Innocent kills | – 50 | (for each) | |
| Points | Rank | Items | ||
|
||||
| x < 100 |  |
3 random ninja items increased | ||
| 100 < | x < 250 |  |
5 random ninja items increased | |
| 250 < | x < 350 |  |
8 random ninja items increased | |
| 350 < | x < 450 |  |
all ninja items & 4 random special items increased | |
| x > 450 |  |
all ninja & special items increased | ||
The fact that you only need 450pts to gain a Grand Master ranking allows you to deduce two formulae regarding how many times you can be spotted and still gain the highest rank. Suppose a mission has x enemies. Then use these formulae to check how many times you can be spotted, s :
| Formula 1 | s < | 20x – 150 |
| 45 | ||
| Formula 2 | s < | 20x – 150 |
| 30 | ||
where Formula 1 calculates s assuming you normally kill any enemy who sees you, and Formula 2 assuming you stealth kill any enemy who spots you. Note these formulae assume you kill every enemy on the level.