Doi-sensei is sick?

1 You Can't Pass! 2 The Missing Diary 3 Shinbei's Treasure 4 Doi-sensei is sick? 5 Narukane Tochidaemon 6 The New Teacher 7 Shinbei's Misunderstanding 8 Where is Shinbei? 9 Leftovers are Unforgivable! 10 A Threesome No Longer! 11 Two Birds with One Stone 12 Dad Comes to Observe 13 A Smiling Face is Very Important 14 Let's Study! 15 Kirimaru's Test 16 Tendon Technique 17 Successful Strategy! 18 Bone Senbei 19 Secret Circle Memo 20 Reversal of Reversal 21 Search for the Fallen Star! 22 Ninjutsu Hide and Seek 23 Shinbei's Adventure 24 I Love Castella 25 I Hate Passwords 26 Happousai's Aim 27 Kirichan in Danger 28 Filled By Love! 29 The Class Leader is the Greatest 30 I Want to Talk! 31 Pursue the Ice Theif 32 A Change of Occupation 33 Shinbei's Cold 34 The Collapsed Traveller 35 The Implement Committee of Terror 36 Scary Inventory 37 I Love Disguises 38 My Tooth Hurts 39 Grilled Slugs 40 Cure the Nervousness! 41 My Sister's Killer 42 Tobe-sensei's Good Example 43 Ninja Makinosuke 44 Tanba Seven Disguises 45 Many Faces 46 Tomorrow there's a Test 47 It Doesn't Look Like Me! 48 Class is Canceled 49 The Mountain Bandit's Favor 50 A Rendezvous? 51 Kisanta's Promise 52 False Tanba of Seven Faces 53 Judging the Requirements of a Tanba Ninja 54 The Swordsman without a Sword 55 Blown Away Test Questions 56 The Yeti who Hated the Cold 57 The Calendar's Shiroshi 58 Uchou no Jutsu 59 Why Can't I Sleep? 60 Ninjutsu Gakuen Observation 61 It's Snowing 62 Wrong Person 63 Father's New Job 64 Thankful Buddha 65 Prophetic Dreams? 66 Kirimaru's Secret 67 Surprise Practice 68 Peach Chestnut 3 Years Persimmon 8 Years 69 Tobe-sensei's Secret 70 Daisan-Kyoueimaru's Fish 71 The Secret of the Turtle Pond 72 To the Dragon's Palace! 73 The Art of 5 Vehicles 74 It Won't Budge 75 I Want to Fix Our Friendship 76 Whose Letter? 77 What is Ninjutsu? 78 The Teacher's Textbook 79 The Pot of Karawatari 80 A Doctor with a Good Reputation 81 Who is the Miser?