| Ladder Series |
| Notes with sequence such as '123456', '234567', or '345678' are what i would term as 'Step-up Ladders'. It can be come in the reverse flow such as '654321', '765432' or '876543' which i would term as 'Step-down Ladders'. |
| Singapore 'Bird' Series $10 with serial number C/62 123456 |
| Singapore 'Bird' Series $1 with serial number A/67 123456 |
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| Singapore 'Bird' Series $1 with serial number E/43 654321 |
| A nice Step-up Ladder. |
| A 'hard to obtain' Step-down Ladder for the 'Bird' Series. |
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| Singapore 'Portrait' Series $2 with serial number 0WW 123456. |